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  • Writing Strings to files in python

    - by Leif Andersen
    I'm getting the following error when trying to write a string to a file in pythion: Traceback (most recent call last): File "export_off.py", line 264, in execute save_off(self.properties.path, context) File "export_off.py", line 244, in save_off primary.write(file) File "export_off.py", line 181, in write variable.write(file) File "export_off.py", line 118, in write file.write(self.value) TypeError: must be bytes or buffer, not str I basically have a string class, which contains a string: class _off_str(object): __slots__ = 'value' def __init__(self, val=""): self.value=val def get_size(self): return SZ_SHORT def write(self,file): file.write(self.value) def __str__(self): return str(self.value) Furthermore, I'm calling that class like this: def write(self, file): for variable in self.variables: variable.write(file) I have no idea what is going on. I've seen other python programs writing strings to files, so why can't this one? Thank you very much for your help.

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  • Why is phpseclib producing incompatible certs?

    - by chacham15
    Why is it that when I try to use a certificate/key pair generated from phpseclib, the OpenSSL server code errors out? Certs/Keys generated from OpenSSL work fine. How do I fix this? Certificate/Key Generation taken straight from phpseclib documentation: <?php include('File/X509.php'); include('Crypt/RSA.php'); // create private key / x.509 cert for stunnel / website $privKey = new Crypt_RSA(); extract($privKey-createKey()); $privKey-loadKey($privatekey); $pubKey = new Crypt_RSA(); $pubKey-loadKey($publickey); $pubKey-setPublicKey(); $subject = new File_X509(); $subject-setDNProp('id-at-organizationName', 'phpseclib demo cert'); //$subject-removeDNProp('id-at-organizationName'); $subject-setPublicKey($pubKey); $issuer = new File_X509(); $issuer-setPrivateKey($privKey); $issuer-setDN($subject-getDN()); $x509 = new File_X509(); //$x509-setStartDate('-1 month'); // default: now //$x509-setEndDate('+1 year'); // default: +1 year $result = $x509-sign($issuer, $subject); echo "the stunnel.pem contents are as follows:\r\n\r\n"; echo $privKey-getPrivateKey(); echo "\r\n"; echo $x509-saveX509($result); echo "\r\n"; ? OpenSSL sample SSL server taken straight from OpenSSL example code: #include <stdio.h #include <unistd.h #include <stdlib.h #include <memory.h #include <errno.h #include <sys/types.h #include <sys/socket.h #include <netinet/in.h #include <arpa/inet.h #include <netdb.h #include <openssl/rsa.h /* SSLeay stuff */ #include <openssl/crypto.h #include <openssl/x509.h #include <openssl/pem.h #include <openssl/ssl.h #include <openssl/err.h #define CHK_NULL(x) if ((x)==NULL) exit (1) #define CHK_ERR(err,s) if ((err)==-1) { perror(s); exit(1); } #define CHK_SSL(err) if ((err)==-1) { ERR_print_errors_fp(stderr); exit(2); } int main (int argc, char *argv[]) { int err; int listen_sd; int sd; struct sockaddr_in sa_serv; struct sockaddr_in sa_cli; size_t client_len; SSL_CTX* ctx; SSL* ssl; X509* client_cert; char* str; char buf [4096]; SSL_METHOD *meth; /* SSL preliminaries. We keep the certificate and key with the context. */ SSL_load_error_strings(); SSLeay_add_ssl_algorithms(); meth = SSLv23_server_method(); ctx = SSL_CTX_new (meth); if (!ctx) { ERR_print_errors_fp(stderr); exit(2); } if (SSL_CTX_use_certificate_file(ctx, argv[1], SSL_FILETYPE_PEM) <= 0) { ERR_print_errors_fp(stderr); exit(3); } if (SSL_CTX_use_PrivateKey_file(ctx, argv[2], SSL_FILETYPE_PEM) <= 0) { ERR_print_errors_fp(stderr); exit(4); } if (!SSL_CTX_check_private_key(ctx)) { fprintf(stderr,"Private key does not match the certificate public key\n"); exit(5); } /* ----------------------------------------------- */ /* Prepare TCP socket for receiving connections */ listen_sd = socket (AF_INET, SOCK_STREAM, 0); CHK_ERR(listen_sd, "socket"); memset (&sa_serv, '\0', sizeof(sa_serv)); sa_serv.sin_family = AF_INET; sa_serv.sin_addr.s_addr = INADDR_ANY; sa_serv.sin_port = htons (1111); /* Server Port number */ err = bind(listen_sd, (struct sockaddr*) &sa_serv, sizeof (sa_serv)); CHK_ERR(err, "bind"); /* Receive a TCP connection. */ err = listen (listen_sd, 5); CHK_ERR(err, "listen"); client_len = sizeof(sa_cli); sd = accept (listen_sd, (struct sockaddr*) &sa_cli, (unsigned int*)&client_len); CHK_ERR(sd, "accept"); close (listen_sd); printf ("Connection from %lx, port %x\n", sa_cli.sin_addr.s_addr, sa_cli.sin_port); /* ----------------------------------------------- */ /* TCP connection is ready. Do server side SSL. */ ssl = SSL_new (ctx); CHK_NULL(ssl); SSL_set_fd (ssl, sd); err = SSL_accept (ssl); CHK_SSL(err); /* Get the cipher - opt */ printf ("SSL connection using %s\n", SSL_get_cipher (ssl)); /* Get client's certificate (note: beware of dynamic allocation) - opt */ client_cert = SSL_get_peer_certificate (ssl); if (client_cert != NULL) { printf ("Client certificate:\n"); str = X509_NAME_oneline (X509_get_subject_name (client_cert), 0, 0); CHK_NULL(str); printf ("\t subject: %s\n", str); OPENSSL_free (str); str = X509_NAME_oneline (X509_get_issuer_name (client_cert), 0, 0); CHK_NULL(str); printf ("\t issuer: %s\n", str); OPENSSL_free (str); /* We could do all sorts of certificate verification stuff here before deallocating the certificate. */ X509_free (client_cert); } else printf ("Client does not have certificate.\n"); /* DATA EXCHANGE - Receive message and send reply. */ err = SSL_read (ssl, buf, sizeof(buf) - 1); CHK_SSL(err); buf[err] = '\0'; printf ("Got %d chars:'%s'\n", err, buf); err = SSL_write (ssl, "I hear you.", strlen("I hear you.")); CHK_SSL(err); /* Clean up. */ close (sd); SSL_free (ssl); SSL_CTX_free (ctx); return 1; } /* EOF - serv.cpp */ This program errors with: (the error is printed out on the call to SSL_write) Connection from 100007f, port a7ff SSL connection using (NONE) Client does not have certificate. Got 0 chars:'' 82673:error:1409E0E5:SSL routines:SSL3_WRITE_BYTES:ssl handshake failure:/SourceCache/OpenSSL098/OpenSSL098-44/src/ssl/s3_pkt.c:539: Here is the relevant code referenced by the error: int ssl3_write_bytes(SSL *s, int type, const void *buf_, int len) { const unsigned char *buf=buf_; unsigned int tot,n,nw; int i; s-rwstate=SSL_NOTHING; tot=s-s3-wnum; s-s3-wnum=0; if (SSL_in_init(s) && !s-in_handshake) { i=s-handshake_func(s); if (i < 0) return(i); if (i == 0) { SSLerr(SSL_F_SSL3_WRITE_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE); return -1; } } ...etc

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  • Why am I getting an IndexOutOfBoundsException here?

    - by Berzerker
    I'm getting an index out of bounds exception thrown and I don't know why, within my replaceValue method below. [null, (10,4), (52,3), (39,9), (78,7), (63,8), (42,2), (50,411)] replacement value test:411 size=7 [null, (10,4), (52,3), (39,9), (78,7), (63,8), (42,2), (50,101)] removal test of :(10,4) [null, (39,9), (52,3), (42,2), (78,7), (63,8), (50,101)] size=6 I try to replace the value again here and get an error... package heappriorityqueue; import java.util.*; public class HeapPriorityQueue<K,V> { protected ArrayList<Entry<K,V>> heap; protected Comparator<K> comp; int size = 0; protected static class MyEntry<K,V> implements Entry<K,V> { protected K key; protected V value; protected int loc; public MyEntry(K k, V v,int i) {key = k; value = v;loc =i;} public K getKey() {return key;} public V getValue() {return value;} public int getLoc(){return loc;} public String toString() {return "(" + key + "," + value + ")";} void setKey(K k1) {key = k1;} void setValue(V v1) {value = v1;} public void setLoc(int i) {loc = i;} } public HeapPriorityQueue() { heap = new ArrayList<Entry<K,V>>(); heap.add(0,null); comp = new DefaultComparator<K>(); } public HeapPriorityQueue(Comparator<K> c) { heap = new ArrayList<Entry<K,V>>(); heap.add(0,null); comp = c; } public int size() {return size;} public boolean isEmpty() {return size == 0; } public Entry<K,V> min() throws EmptyPriorityQueueException { if (isEmpty()) throw new EmptyPriorityQueueException("Priority Queue is Empty"); return heap.get(1); } public Entry<K,V> insert(K k, V v) { size++; Entry<K,V> entry = new MyEntry<K,V>(k,v,size); heap.add(size,entry); upHeap(size); return entry; } public Entry<K,V> removeMin() throws EmptyPriorityQueueException { if (isEmpty()) throw new EmptyPriorityQueueException("Priority Queue is Empty"); if (size == 1) return heap.remove(1); Entry<K,V> min = heap.get(1); heap.set(1, heap.remove(size)); size--; downHeap(1); return min; } public V replaceValue(Entry<K,V> e, V v) throws InvalidEntryException, EmptyPriorityQueueException { // replace the value field of entry e in the priority // queue with the given value v, and return the old value This is where I am getting the IndexOutOfBounds exception, on heap.get(i); if (isEmpty()){ throw new EmptyPriorityQueueException("Priority Queue is Empty."); } checkEntry(e); int i = e.getLoc(); Entry<K,V> entry=heap.get(((i))); V oldVal = entry.getValue(); K key=entry.getKey(); Entry<K,V> insert = new MyEntry<K,V>(key,v,i); heap.set(i, insert); return oldVal; } public K replaceKey(Entry<K,V> e, K k) throws InvalidEntryException, EmptyPriorityQueueException, InvalidKeyException { // replace the key field of entry e in the priority // queue with the given key k, and return the old key if (isEmpty()){ throw new EmptyPriorityQueueException("Priority Queue is Empty."); } checkKey(k); checkEntry(e); K oldKey=e.getKey(); int i = e.getLoc(); Entry<K,V> entry = new MyEntry<K,V>(k,e.getValue(),i); heap.set(i,entry); downHeap(i); upHeap(i); return oldKey; } public Entry<K,V> remove(Entry<K,V> e) throws InvalidEntryException, EmptyPriorityQueueException{ // remove entry e from priority queue and return it if (isEmpty()){ throw new EmptyPriorityQueueException("Priority Queue is Empty."); } MyEntry<K,V> entry = checkEntry(e); if (size==1){ return heap.remove(size--); } int i = e.getLoc(); heap.set(i, heap.remove(size--)); downHeap(i); return entry; } protected void upHeap(int i) { while (i > 1) { if (comp.compare(heap.get(i/2).getKey(), heap.get(i).getKey()) <= 0) break; swap(i/2,i); i = i/2; } } protected void downHeap(int i) { int smallerChild; while (size >= 2*i) { smallerChild = 2*i; if ( size >= 2*i + 1) if (comp.compare(heap.get(2*i + 1).getKey(), heap.get(2*i).getKey()) < 0) smallerChild = 2*i+1; if (comp.compare(heap.get(i).getKey(), heap.get(smallerChild).getKey()) <= 0) break; swap(i, smallerChild); i = smallerChild; } } protected void swap(int j, int i) { heap.get(j).setLoc(i); heap.get(i).setLoc(j); Entry<K,V> temp; temp = heap.get(j); heap.set(j, heap.get(i)); heap.set(i, temp); } public String toString() { return heap.toString(); } protected MyEntry<K,V> checkEntry(Entry<K,V> ent) throws InvalidEntryException { if(ent == null || !(ent instanceof MyEntry)) throw new InvalidEntryException("Invalid entry."); return (MyEntry)ent; } protected void checkKey(K key) throws InvalidKeyException{ try{comp.compare(key,key);} catch(Exception e){throw new InvalidKeyException("Invalid key.");} } }

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  • how to write the code for this program specially in mathematica? [closed]

    - by asd
    I implemented a solution to the problem below in Mathematica, but it takes a very long time (hours) to compute f of kis or the set B for large numbers. Somebody suggested that implementing this in C++ resulted in a solution in less than 10 minutes. Would C++ be a good language to learn to solve these problems, or can my Mathematica code be improved to fix the performance issues? I don't know anything about C or C++ and it should be difficult to start to learn this languages. I prefer to improve or write new code in mathematica. Problem Description Let $f$ be an arithmetic function and A={k1,k2,...,kn} are integers in increasing order. Now I want to start with k1 and compare f(ki) with f(k1). If f(ki)f(k1), put ki as k1. Now start with ki, and compare f(kj) with f(ki), for ji. If f(kj)f(ki), put kj as ki, and repeat this procedure. At the end we will have a sub sequence B={L1,...,Lm} of A by this property: f(L(i+1))f(L(i)), for any 1<=i<=m-1 For example, let f is the divisor function of integers. Here I put some part of my code and this is just a sample and the question in my program could be more larger than these: «««««««««««««««««««««««««««««««««««« f[n_] := DivisorSigma[0, n]; g[n_] := Product[Prime[i], {i, 1, PrimePi[n]}]; k1 = g[67757] g[353] g[59] g[19] g[11] g[7] g[5]^2 6^3 2^7; k2 = g[67757] g[353] g[59] g[19] g[11] g[7] g[5] 6^5 2^7; k3 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5] 6^4 2^7; k4 = g[67759] g[349] g[53] g[19] g[11] g[7] g[5] 6^5 2^6; k5 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5] 6^4 2^8; k6 = g[67759] g[349] g[53] g[19] g[11] g[7] g[5]^2 6^3 2^7; k7 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5] 6^5 2^6; k8 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5] 6^4 2^9; k9 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5]^2 6^3 2^7; k10 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5] 6^5 2^7; k11 = g[67759] g[349] g[53] g[19] g[11] g[7] g[5]^2 6^4 2^6; k12 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5]^2 6^3 2^8; k13 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5]^2 6^4 2^6; k14 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5]^2 6^3 2^9; k15 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5]^2 6^4 2^7; k16 = g[67757] g[359] g[53] g[23] g[11] g[7] g[5] 6^4 2^8; k17 = g[67757] g[359] g[59] g[19] g[11] g[7] g[5] 6^4 2^7; k18 = g[67757] g[359] g[53] g[23] g[11] g[7] g[5] 6^4 2^9; k19 = g[67759] g[353] g[53] g[19] g[11] g[7] g[5] 6^4 2^6; k20 = g[67763] g[347] g[53] g[19] g[11] g[7] g[5] 6^4 2^7; k = Table[k1, k2, k3, k4, k5, k6, k7, k8, k9, k10, k11, k12, k13, k14, k15, k16, k17, k18, k19, k20]; i = 1; count = 0; For[j = i, j <= 20, j++, If[f[k[[j]]] - f[k[[i]]] > 0, i = j; Print["k",i]; count = count + 1]]; Print["count= ", count] ««««««««««««««««««««««««««««««««««««

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  • Is Visual Source Safe (The latest Version) really that bad? Why? What's the Best Alternative? Why? [closed]

    - by hanzolo
    Over the years I've constantly heard horror stories, had people say "Real Programmers Dont Use VSS", and so on. BUT, then in the workplace I've worked at two companies, one, a very well known public facing high traffic website, and another high end Financial Services "Web-Based" hosted solution catering to some very large, very well known companies, which is where I currently Reside and everything's working just fine (KNOCK KNOCK!!). I'm constantly interfacing with EXTREMELY Old technology with some of these financial institutions.. OLD LIKE YOU WOULDN'T BELIEVE.. which leads me to the conclusion that if it works "LEAVE IT", and that maybe there's some value in old technology? at least enough value to overrule a rewrite!? right?? Is there something fundamentally flawed with the underlying technology that VSS uses? I have a feeling that if i said "someone said VSS Sucks" they would beg to differ, most likely give me this look like i dont know -ish, and I'd never gain back their respect and my credibility (well, that'll be hard to blow.. lol), BUT, give me an argument that I can take to someone whose been coding for 30 years, that builds Platforms that leverage current technology (.NET 3.5 / SQL 2008 R2 ), write's their own ORM with scaffolding and is able to provide a quality platform that supports thousands of concurrent users on a multi-tenant hosted solution, and does not agree with any benefits from having Source Control Integrated, and yet uses the Infamous Visual Source Safe. I have extensive experience with TFS up to 2010, and honestly I think it's great when a team (beyond developers) can embrace it. I've worked side by side with someone whose a die hard SVN'r and from a purist standpoint, I see the beauty in it (I need a bit more, out of my SS, but it surely suffices). So, why are such smarties not running away from Visual Source Safe? surely if it was so bad, it would've have been realized by now, and I would not be sitting here with this simple old, Check In, Check Out, Version Resistant, Label Intensive system. But here I am... I would love to drop an argument that would be the end all argument, but if it's a matter of opinion and personal experience, there seems to be too much leeway for keeping VSS. UPDATE: I guess the best case is to have the VSS supporters check other people's experiences and draw from that until we (please no) experience the breaking factor ourselves. Until then, i wont be engaging in a discussion to migrate off of VSS.. UPDATE 11-2012: So i was able to convince everyone at my work place that since MS is sun downing Visual Source Safe it might be time to migrate over to TFS. I was able to convince them and have recently upgraded our team to Visual Studio 2012 and TFS 2012. The migration was fairly painless, had to run analyze.exe which found a bunch of errors (not sure they'll ever affect the project) and then manually run the VSSConverter.exe. Again, painless, except it took 16 hours to migrate 5 years worth of everything.. and now we're on TFS.. much more integrated.. much more cooler.. so all in all, VSS served it's purpose for years without hick-up. There were no horror stories and Visual Source Save as source control worked just fine. so to all the nay sayers (me included). there's nothing wrong with using VSS. i wouldnt start a new project with it, and i would definitely consider migrating to TFS. (it's really not super difficult and a new "wizard" type converter is due out any day now so migrating should be painless). But from my experience, it worked just fine and got the job done.

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  • Why isn't my operator overloading working properly?

    - by Mithrax
    I have the following Polynomial class I'm working on: #include <iostream> using namespace std; class Polynomial { //define private member functions private: int coef[100]; // array of coefficients // coef[0] would hold all coefficients of x^0 // coef[1] would hold all x^1 // coef[n] = x^n ... int deg; // degree of polynomial (0 for the zero polynomial) //define public member functions public: Polynomial::Polynomial() //default constructor { for ( int i = 0; i < 100; i++ ) { coef[i] = 0; } } void set ( int a , int b ) //setter function { //coef = new Polynomial[b+1]; coef[b] = a; deg = degree(); } int degree() { int d = 0; for ( int i = 0; i < 100; i++ ) if ( coef[i] != 0 ) d = i; return d; } void print() { for ( int i = 99; i >= 0; i-- ) { if ( coef[i] != 0 ) { cout << coef[i] << "x^" << i << " "; } } } // use Horner's method to compute and return the polynomial evaluated at x int evaluate ( int x ) { int p = 0; for ( int i = deg; i >= 0; i-- ) p = coef[i] + ( x * p ); return p; } // differentiate this polynomial and return it Polynomial differentiate() { if ( deg == 0 ) { Polynomial t; t.set ( 0, 0 ); return t; } Polynomial deriv;// = new Polynomial ( 0, deg - 1 ); deriv.deg = deg - 1; for ( int i = 0; i < deg; i++ ) deriv.coef[i] = ( i + 1 ) * coef[i + 1]; return deriv; } Polynomial Polynomial::operator + ( Polynomial b ) { Polynomial a = *this; //a is the poly on the L.H.S Polynomial c; for ( int i = 0; i <= a.deg; i++ ) c.coef[i] += a.coef[i]; for ( int i = 0; i <= b.deg; i++ ) c.coef[i] += b.coef[i]; c.deg = c.degree(); return c; } Polynomial Polynomial::operator += ( Polynomial b ) { Polynomial a = *this; //a is the poly on the L.H.S Polynomial c; for ( int i = 0; i <= a.deg; i++ ) c.coef[i] += a.coef[i]; for ( int i = 0; i <= b.deg; i++ ) c.coef[i] += b.coef[i]; c.deg = c.degree(); for ( int i = 0; i < 100; i++) a.coef[i] = c.coef[i]; a.deg = a.degree(); return a; } Polynomial Polynomial::operator -= ( Polynomial b ) { Polynomial a = *this; //a is the poly on the L.H.S Polynomial c; for ( int i = 0; i <= a.deg; i++ ) c.coef[i] += a.coef[i]; for ( int i = 0; i <= b.deg; i++ ) c.coef[i] -= b.coef[i]; c.deg = c.degree(); for ( int i = 0; i < 100; i++) a.coef[i] = c.coef[i]; a.deg = a.degree(); return a; } Polynomial Polynomial::operator *= ( Polynomial b ) { Polynomial a = *this; //a is the poly on the L.H.S Polynomial c; for ( int i = 0; i <= a.deg; i++ ) for ( int j = 0; j <= b.deg; j++ ) c.coef[i+j] += ( a.coef[i] * b.coef[j] ); c.deg = c.degree(); for ( int i = 0; i < 100; i++) a.coef[i] = c.coef[i]; a.deg = a.degree(); return a; } Polynomial Polynomial::operator - ( Polynomial b ) { Polynomial a = *this; //a is the poly on the L.H.S Polynomial c; for ( int i = 0; i <= a.deg; i++ ) c.coef[i] += a.coef[i]; for ( int i = 0; i <= b.deg; i++ ) c.coef[i] -= b.coef[i]; c.deg = c.degree(); return c; } Polynomial Polynomial::operator * ( Polynomial b ) { Polynomial a = *this; //a is the poly on the L.H.S Polynomial c; for ( int i = 0; i <= a.deg; i++ ) for ( int j = 0; j <= b.deg; j++ ) c.coef[i+j] += ( a.coef[i] * b.coef[j] ); c.deg = c.degree(); return c; } }; int main() { Polynomial a, b, c, d; a.set ( 7, 4 ); //7x^4 a.set ( 1, 2 ); //x^2 b.set ( 6, 3 ); //6x^3 b.set ( -3, 2 ); //-3x^2 c = a - b; // (7x^4 + x^2) - (6x^3 - 3x^2) a -= b; c.print(); cout << "\n"; a.print(); cout << "\n"; c = a * b; // (7x^4 + x^2) * (6x^3 - 3x^2) c.print(); cout << "\n"; d = c.differentiate().differentiate(); d.print(); cout << "\n"; cout << c.evaluate ( 2 ); //substitue x with 2 cin.get(); } Now, I have the "-" operator overloaded and it works fine: Polynomial Polynomial::operator - ( Polynomial b ) { Polynomial a = *this; //a is the poly on the L.H.S Polynomial c; for ( int i = 0; i <= a.deg; i++ ) c.coef[i] += a.coef[i]; for ( int i = 0; i <= b.deg; i++ ) c.coef[i] -= b.coef[i]; c.deg = c.degree(); return c; } However, I'm having difficulty with my "-=" operator: Polynomial Polynomial::operator -= ( Polynomial b ) { Polynomial a = *this; //a is the poly on the L.H.S Polynomial c; for ( int i = 0; i <= a.deg; i++ ) c.coef[i] += a.coef[i]; for ( int i = 0; i <= b.deg; i++ ) c.coef[i] -= b.coef[i]; c.deg = c.degree(); // overwrite value of 'a' with the newly computed 'c' before returning 'a' for ( int i = 0; i < 100; i++) a.coef[i] = c.coef[i]; a.deg = a.degree(); return a; } I just slightly modified my "-" operator method to overwrite the value in 'a' and return 'a', and just use the 'c' polynomial as a temp. I've put in some debug print statement and I confirm that at the time of computation, both: c = a - b; and a -= b; are computed to the same value. However, when I go to print them, their results are different: Polynomial a, b; a.set ( 7, 4 ); //7x^4 a.set ( 1, 2 ); //x^2 b.set ( 6, 3 ); //6x^3 b.set ( -3, 2 ); //-3x^2 c = a - b; // (7x^4 + x^2) - (6x^3 - 3x^2) a -= b; c.print(); cout << "\n"; a.print(); cout << "\n"; Result: 7x^4 -6x^3 4x^2 7x^4 1x^2 Why is my c = a - b and a -= b giving me different results when I go to print them?

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  • Why Mac OS X is referred to as the developer's OS? [closed]

    - by dbramhall
    Possible Duplicate: Why do programmers use or recommend Mac OS X? I have heard people referring to Mac OS X as the 'developer's operating system' and I was wondering why? I have been using Mac OS X for years but I only see Mac OS X as a developer's OS if the developer tools are installed, without them it's not really a developer's OS. Also, the Terminal is obviously a huge plus for developers but is this it?

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  • Why is my dual-boot Ubuntu partition showing up as a peripheral "root.disk"?

    - by Don
    I recently installed Ubuntu 12.04, which I had been booting from a usb key, as a dual-boot on my machine running Windows 7. From what I had read online while researching, I was prepared to have to shrink the Windows partition and all that. But I never had to - it really was just a few clicks here and there and it was installed. I'm still pretty confused about it, but whatever, it worked, and the two peacefully coexist on my machine, and I have broken things to fix before I worry about fixing unbroken things. So yesterday I got it in my head to look at my partitions (I was considering making an all new partition to install the Windows 8 Release Preview). What I saw confused me. Here's a screenshot of the disk utility. At this moment, there is nothing connected to my computer, and nothing in any of the optical drives/ports/card readers/etc. Can you help me figure out what's going on here? Don's Machine is, I believe, my Windows partition - that's the name I assigned my machine from Windows Explorer. PQSERVICE is from what I can find online also Windows, but having to do with backup. And SYSTEM REQUIRED, if I browse it in Ubuntu, is definitely something to do with booting, and I believe it is also Windows'. According to the sizes shown, those three together should use up my 500 GB HD. Then further down, as a "peripheral device", it lists that 31 GB disk. This is obviously my Ubuntu (Model:Linux Loop:root.disk), but why is it showing up as a peripheral? So, to sum up those questions and to add some more random ones I had: Why is Ubuntu showing up as a peripheral device? If the Windows sections take up all 500 GB, where does Ubuntu live? If I renamed the disk partitions, would my life become a nightmare (seriously - can I safely rename them)? Why didn't I have to resize the Windows partition in the first place? Would giving Ubuntu more space improve its performance (it hangs alot)? Is it possible to have a partition for each OS (Windows 7 & 8, Ubuntu), a partition for files, and a separate partition for backups? Is this towards the good or bad idea end of the spectrum? @Elfy, would that explain why it keeps hanging? I guess I'll backup my files, rip it out, and reinstall it correctly later on today.

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  • Why doesn't Mozilla release .deb and .rpm packages for their software?

    - by ushabtay
    i use and enjoy Firefox on my Ubuntu 10.04.2 laptop (although Firefox needs work for the Linux/Ubuntu version..) Yet i realize that in comparison to other pieces of software that have an "Ubuntu/Debian" version (.deb file, and usually .rpm files as well), i don't see it in one of the most profound assets of the FLOSS world. The Question is - Why? If Chrom/ium can - why can't they? Easier to get up-to-date software and features and so forth.. cheers,

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  • It's 2012.. why do we still need hacks like Micro Clearfix to do simple things? [closed]

    - by user72245
    I'm just dipping back into front-end development again. I seriously can't believe we're at "HTML5" yet the most basic thing imaginable - horizontal floating DIVs, still requires crazy esoteric hacks to work correctly? http://nicolasgallagher.com/micro-clearfix-hack/ Like this... why is this necessary? Why can't browsers just grow up and handle 3 dynamically-sized DIVs floating horizontally in a container row?

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  • Why Is it better to use unreadable bytes for client server communication?

    - by Alessa
    I'm composing communication lyrics for client-server and what am I thinking about: "authme username passord" (maybe encrytped) "accept" "get archive of H2O from 03.02.2005 to 20.12.2064" transferring binary structure or "error descrtiption" why I always need to do something like 0x0FA52FD + CRC 0x0D34423 + CRC ... I can see some secure reasons but I think it's not the real reason so why I can't use strings in client-server communication?

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  • Why does google does not ignore the word "languages", although I have set to ignore it in advanced search settings

    - by jitendra1234
    Why does google does not ignore the word "languages", although I have set to ignore it in advanced search settings. here is the term I am using in google search: -languages site:http://en.wikipedia.org/wiki/ and here is the first result where the word "languages" is still present, (you can do a quick crtl+F to find out) http://en.wikipedia.org/wiki/Walter_Bedell_Smith I am just curious to know why google have not ignored the word "languages"?

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  • Why all of my ports are not open or reachable? how can i open them

    - by Rev3rse
    I was testing the ports because WoW(3724 TCP 6112 TCP 6881-6999 TCP) couldn't connect to the internet so i downloaded PFPortChecker application and run it using Wine(1.3) and after i tried to check every port it seems like it's not reachable/closed why is that? my firewall is off so why is this happening? how can i open these ports? and how can i see if these ports are opened or not and the important thing is how can i know which application is using them

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  • Why do I have to add a PPA twice (once to add it to the list of repo, second time to fix a BAD GPG)

    - by Luis Alvarado
    I notice the following: I add a ppa using add-apt-repository, for example the wine ppa, mozilla security, nvidia drivers, etc.. When I go to the Update Manager and tell it to CHECK for updates it throws me a PPA error. To solve the error I add the same PPA again. Why do I have to add the PPA again (This also can be done by adding the received key alone with apt-key) but why does this problem happen anyway.

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  • why there is no power operator in java / c ++?

    - by RanZilber
    While there is such operator - ** in Python , i was wondering why java and c++ havent got one too. It is easy to make one for classes you define in C++ with operator overloading ( and i believe such thing is possible also in java) , but when talking about primitive types such as int, double and so on , you'll have to use library function like Math.power (and usaully have to cast both to double). So - why not define such operator for primitive types ?

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  • Why DbContext object shouldn't be referred in Service Layer?

    - by nazmoonnoor
    I've been looking for some implementations of Service Layer and Controller interaction in blogs and in some open source projects. All of them seem to refer DbContext object in repository classes but avoided to use in service classes. Service classes essentially using a IQueryable<T> references of DbSet<T>. I want to know why this practice is good and why DbContext shouldn't have a reference in Service Layer.

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  • Why C++ people loves multithreading when it comes to performances?

    - by user1849534
    I have a question, it's about why programmers seems to love concurrency and multi-threaded programs in general. I'm considering 2 main approach here: an async approach basically based on signals, or just an async approach as called by many papers and languages like the new C# 5.0 for example, and a "companion thread" that maanges the policy of your pipeline a concurrent approach or multi-threading approach I will just say that I'm thinking about the hardware here and the worst case scenario, and I have tested this 2 paradigms myself, the async paradigm is a winner at the point that I don't get why people 90% of the time talk about concurrency when they wont to speed up things or make a good use of their resources. I have tested multi-threaded programs and async program on an old machine with an Intel quad-core that doesn't offer a memory controller inside the CPU, the memory is managed entirely by the motherboard, well in this case performances are horrible with a multi-threaded application, even a relatively low number of threads like 3-4-5 can be a problem, the application is unresponsive and is just slow and unpleasant. A good async approach is, on the other hand, probably not faster but it's not worst either, my application just waits for the result and doesn't hangs, it's responsive and there is a much better scaling going on. I have also discovered that a context change in the threading world it's not that cheap in real world scenario, it's infact quite expensive especially when you have more than 2 threads that need to cycle and swap among each other to be computed. On modern CPUs the situation it's not really that different, the memory controller it's integrated but my point is that an x86 CPUs is basically a serial machine and the memory controller works the same way as with the old machine with an external memory controller on the motherboard. The context switch is still a relevant cost in my application and the fact that the memory controller it's integrated or that the newer CPU have more than 2 core it's not bargain for me. For what i have experienced the concurrent approach is good in theory but not that good in practice, with the memory model imposed by the hardware, it's hard to make a good use of this paradigm, also it introduces a lot of issues ranging from the use of my data structures to the join of multiple threads. Also both paradigms do not offer any security abut when the task or the job will be done in a certain point in time, making them really similar from a functional point of view. According to the X86 memory model, why the majority of people suggest to use concurrency with C++ and not just an async aproach ? Also why not considering the worst case scenario of a computer where the context switch is probably more expensive than the computation itself ?

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  • Why can any user read the content in my homedir?

    - by Digiplace
    Why is it that the default setting makes it possible for user A to look in the homedir of user B and vice versa? And furthermore..that user can not only look into the homedir of another user, he can also open any document he wants to. It feels very insecure to me. There should be more privacy for users. I know how to prevent this situation, but it puzzles me why this should be possible in the first place.

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  • Why keylistener is not working here?

    - by swift
    i have implemented keylistener interface and implemented all the needed methods but when i press the key nothing happens here, why? package swing; import java.awt.Color; import java.awt.Dimension; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.GridLayout; import java.awt.Point; import java.awt.RenderingHints; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.KeyEvent; import java.awt.event.KeyListener; import java.awt.event.MouseEvent; import java.awt.event.MouseListener; import java.awt.event.MouseMotionListener; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import java.awt.image.BufferedImage; import javax.swing.BorderFactory; import javax.swing.BoxLayout; import javax.swing.ImageIcon; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLayeredPane; import javax.swing.JPanel; import javax.swing.JTextArea; class Paper extends JPanel implements MouseListener,MouseMotionListener,ActionListener,KeyListener { static BufferedImage image; String shape; Color color=Color.black; Point start; Point end; Point mp; Button elipse=new Button("elipse"); int x[]=new int[50]; int y[]=new int[50]; Button rectangle=new Button("rect"); Button line=new Button("line"); Button roundrect=new Button("roundrect"); Button polygon=new Button("poly"); Button text=new Button("text"); ImageIcon erasericon=new ImageIcon("images/eraser.gif"); JButton erase=new JButton(erasericon); JButton[] colourbutton=new JButton[9]; String selected; Point label; String key; int ex,ey;//eraser //DatagramSocket dataSocket; JButton button = new JButton("test"); JLayeredPane layerpane; Point p=new Point(); int w,h; public Paper() { JFrame frame=new JFrame("Whiteboard"); frame.setVisible(true); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setSize(640, 480); frame.setBackground(Color.black); layerpane=frame.getLayeredPane(); setWidth(539,444); setBounds(69,0,555,444); layerpane.add(this,new Integer(2)); layerpane.add(this.addButtons(),new Integer(0)); setLayout(null); setOpaque(false); addMouseListener(this); addMouseMotionListener(this); setFocusable(true); addKeyListener(this); System.out.println(isFocusable()); setBorder(BorderFactory.createLineBorder(Color.black)); } public void paintComponent(Graphics g) { try { super.paintComponent(g); g.drawImage(image, 0, 0, this); Graphics2D g2 = (Graphics2D)g; if(color!=null) g2.setPaint(color); if(start!=null && end!=null) { if(selected==("elipse")) g2.drawOval(start.x, start.y,(end.x-start.x),(end.y-start.y)); else if(selected==("rect")) g2.drawRect(start.x, start.y, (end.x-start.x),(end.y-start.y)); else if(selected==("rrect")) g2.drawRoundRect(start.x, start.y, (end.x-start.x),(end.y-start.y),11,11); else if(selected==("line")) g2.drawLine(start.x,start.y,end.x,end.y); else if(selected==("poly")) g2.drawPolygon(x,y,2); } } catch(Exception e) {} } //Function to draw the shape on image public void draw() { Graphics2D g2 = image.createGraphics(); g2.setPaint(color); if(start!=null && end!=null) { if(selected=="line") g2.drawLine(start.x, start.y, end.x, end.y); else if(selected=="elipse") g2.drawOval(start.x, start.y, (end.x-start.x),(end.y-start.y)); else if(selected=="rect") g2.drawRect(start.x, start.y, (end.x-start.x),(end.y-start.y)); else if(selected==("rrect")) g2.drawRoundRect(start.x, start.y, (end.x-start.x),(end.y-start.y),11,11); else if(selected==("poly")) g2.drawPolygon(x,y,2); } if(label!=null) { JTextArea textarea=new JTextArea(); if(selected==("text")) { textarea.setBounds(label.x, label.y, 50, 50); textarea.setMaximumSize(new Dimension(100,100)); textarea.setBackground(new Color(237,237,237)); add(textarea); g2.drawString("key",label.x,label.y); } } start=null; repaint(); g2.dispose(); } public void text() { System.out.println(label); } //Function which provides the erase functionality public void erase() { Graphics2D pic=(Graphics2D) image.getGraphics(); Color erasecolor=new Color(237,237,237); pic.setPaint(erasecolor); if(start!=null) pic.fillRect(start.x, start.y, 10, 10); } //To set the size of the image public void setWidth(int x,int y) { System.out.println("("+x+","+y+")"); w=x; h=y; image = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB); } //Function to add buttons into the panel, calling this function returns a panel public JPanel addButtons() { JPanel buttonpanel=new JPanel(); buttonpanel.setMaximumSize(new Dimension(70,70)); JPanel shape=new JPanel(); JPanel colourbox=new JPanel(); shape.setLayout(new GridLayout(4,2)); shape.setMaximumSize(new Dimension(70,140)); colourbox.setLayout(new GridLayout(3,3)); colourbox.setMaximumSize(new Dimension(70,70)); buttonpanel.setLayout(new BoxLayout(buttonpanel,BoxLayout.Y_AXIS)); elipse.addActionListener(this); elipse.setToolTipText("Elipse"); rectangle.addActionListener(this); rectangle.setToolTipText("Rectangle"); line.addActionListener( this); line.setToolTipText("Line"); erase.addActionListener(this); erase.setToolTipText("Eraser"); roundrect.addActionListener(this); roundrect.setToolTipText("Round rect"); polygon.addActionListener(this); polygon.setToolTipText("Polygon"); text.addActionListener(this); text.setToolTipText("Text"); shape.add(elipse); shape.add(rectangle); shape.add(line); shape.add(erase); shape.add(roundrect); shape.add(polygon); shape.add(text); buttonpanel.add(shape); for(int i=0;i<9;i++) { colourbutton[i]=new JButton(); colourbox.add(colourbutton[i]); if(i==0) colourbutton[0].setBackground(Color.black); else if(i==1) colourbutton[1].setBackground(Color.white); else if(i==2) colourbutton[2].setBackground(Color.red); else if(i==3) colourbutton[3].setBackground(Color.orange); else if(i==4) colourbutton[4].setBackground(Color.blue); else if(i==5) colourbutton[5].setBackground(Color.green); else if(i==6) colourbutton[6].setBackground(Color.pink); else if(i==7) colourbutton[7].setBackground(Color.magenta); else if(i==8) colourbutton[8].setBackground(Color.cyan); colourbutton[i].addActionListener(this); } buttonpanel.add(colourbox); buttonpanel.setBounds(0, 0, 70, 210); return buttonpanel; } public void mouseClicked(MouseEvent e) { if(selected=="text") { label=new Point(); label=e.getPoint(); draw(); } } @Override public void mouseEntered(MouseEvent arg0) { } public void mouseExited(MouseEvent arg0) { } public void mousePressed(MouseEvent e) { if(selected=="line"||selected=="erase"||selected=="text") { start=e.getPoint(); } else if(selected=="elipse"||selected=="rect"||selected=="rrect") { mp = e.getPoint(); } else if(selected=="poly") { x[0]=e.getX(); y[0]=e.getY(); } } public void mouseReleased(MouseEvent e) { if(start!=null) { if(selected=="line") { end=e.getPoint(); } else if(selected=="elipse"||selected=="rect"||selected=="rrect") { end.x = Math.max(mp.x,e.getX()); end.y = Math.max(mp.y,e.getY()); } else if(selected=="poly") { x[1]=e.getX(); y[1]=e.getY(); } draw(); } } public void mouseDragged(MouseEvent e) { if(end==null) end = new Point(); if(start==null) start = new Point(); if(selected=="line") { end=e.getPoint(); } else if(selected=="erase") { start=e.getPoint(); erase(); } else if(selected=="elipse"||selected=="rect"||selected=="rrect") { start.x = Math.min(mp.x,e.getX()); start.y = Math.min(mp.y,e.getY()); end.x = Math.max(mp.x,e.getX()); end.y = Math.max(mp.y,e.getY()); } else if(selected=="poly") { x[1]=e.getX(); y[1]=e.getY(); } repaint(); } public void mouseMoved(MouseEvent arg0) {} public void actionPerformed(ActionEvent e) { if(e.getSource()==elipse) selected="elipse"; else if(e.getSource()==line) selected="line"; else if(e.getSource()==rectangle) selected="rect"; else if(e.getSource()==erase) { selected="erase"; System.out.println(selected); erase(); } else if(e.getSource()==roundrect) selected="rrect"; else if(e.getSource()==polygon) selected="poly"; else if(e.getSource()==text) selected="text"; if(e.getSource()==colourbutton[0]) color=Color.black; else if(e.getSource()==colourbutton[1]) color=Color.white; else if(e.getSource()==colourbutton[2]) color=Color.red; else if(e.getSource()==colourbutton[3]) color=Color.orange; else if(e.getSource()==colourbutton[4]) color=Color.blue; else if(e.getSource()==colourbutton[5]) color=Color.green; else if(e.getSource()==colourbutton[6]) color=Color.pink; else if(e.getSource()==colourbutton[7]) color=Color.magenta; else if(e.getSource()==colourbutton[8]) color=Color.cyan; } @Override public void keyPressed(KeyEvent e) { System.out.println("pressed"); } @Override public void keyReleased(KeyEvent e) { System.out.println("key released"); } @Override public void keyTyped(KeyEvent e) { System.out.println("Typed"); } public static void main(String[] a) { new Paper(); } } class Button extends JButton { String name; public Button(String name) { this.name=name; } public void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2 = (Graphics2D)g; g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); //g2.setStroke(new BasicStroke(1.2f)); if (name == "line") g.drawLine(5,5,30,30); if (name == "elipse") g.drawOval(5,7,25,20); if (name== "rect") g.drawRect(5,5,25,23); if (name== "roundrect") g.drawRoundRect(5,5,25,23,10,10); int a[]=new int[]{20,9,20,23,20}; int b[]=new int[]{9,23,25,20,9}; if (name== "poly") g.drawPolyline(a, b, 5); if (name== "text") g.drawString("Text",5, 22); } }

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  • Updating resources in SharpDX - why can I not map a dynamic texture?

    - by sebf
    I am trying to map a Texture2D resource in DirectX11 via SharpDX. The resource is declared as a ShaderResource, with Default usage and the 'Write' CPU flag specified. My call however fails with a generic exception from SharpDX: _Parent.Context.MapSubresource(_Resource, 0, SharpDX.Direct3D11.MapMode.Write, SharpDX.Direct3D11.MapFlags.None, out stream); I see from this question that it is supported. The MSDN docs and this other question hint that instead of using Context.MapSubresource() I should be using Texture2D.Map(), however, the DirectX11 Texture2D class does not define Map() (though it does for the DX10 equivalent). If I call the above with MapMode.WriteDiscard, the call succeeds but in this case the previous content of the texture is lost, which is no good when I only want to update a section of it. Has the Map() method been removed in DirectX11 or am I looking in the wrong place? Is the MapSubresource() method unsuitable or am I using it wrong?

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  • Why is filesystem preferred for logs instead of RDBMS?

    - by Yasir
    Question should be clear from its title. For example Apache saves its access and error logs in files instead of RDBMS no matter on how large or small scale it is being utilized. For RDMS we just have to write SQL queries and it will do the work while for files we must decide a particular format and then write regex or may be parsers to manipulate them. And those might even fail in particular circumstances if great care was not paid. Yet everyone seems to prefer filesystem for maintaining the logs. I am not biased against any of these methods but I would like to know why it is practiced like this. Is it speed or maintainability or something else?

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  • Why is this Exception?- The relationship between the two objects cannot be defined because they are

    - by dev-1787
    I m getting this Exception-"The relationship between the two objects cannot be defined because they are attached to different ObjectContext objects." I ve user table and country table. The countryid is referred in user table. I am getting the above Exception when I am trying to add entry in user table. This is my code- using (MyContext _db = new MyContext ()) { User user = User .CreateUser(0, Name, address, city, 0, 0, email, zip); Country country = _db.Country.Where("it.Id=@Id", new ObjectParameter("Id",countryId)).First(); user.Country = country; State state = _db.State.Where("it.Id=@Id", new ObjectParameter("Id", stateId)).First(); user.State = state; _db.AddToUser(user );//Here I am getting that Exception _db.SaveChanges(); }

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  • Why SetUnhandledExceptionFilter cannot capture some exception but AddVectoredExceptionHandler can do

    - by wrongite
    I have experienced a problem that the function I passed to the SetUnhandledExceptionFilter didn't get called when the exception code c0000374 raising. But it works fine with the exception code c0000005. Then I tried to use the AddVectoredExceptionHandler instead, and it didn't have the problem, the handler function get called correctly. Is it the API bug? Can I use AddVectoredExceptionHandler instead of SetUnhandledExceptionFilter everywhere? The both functions work correctly with // Exception code c0000005 int* p1 = NULL; *p1 = 99; Only AddVectoredExceptionHandler can capture this exception. // Exception code c0000374 int* p2 = new int; delete p2; delete p2; Test program. #include <tchar.h> #include <fstream> #include <Windows.h> LONG WINAPI VectoredExceptionHandler(PEXCEPTION_POINTERS pExceptionInfo) { std::ofstream f; f.open("VectoredExceptionHandler.txt", std::ios::out | std::ios::trunc); f << std::hex << pExceptionInfo->ExceptionRecord->ExceptionCode << std::endl; f.close(); return EXCEPTION_CONTINUE_SEARCH; } LONG WINAPI TopLevelExceptionHandler(PEXCEPTION_POINTERS pExceptionInfo) { std::ofstream f; f.open("TopLevelExceptionHandler.txt", std::ios::out | std::ios::trunc); f << std::hex << pExceptionInfo->ExceptionRecord->ExceptionCode << std::endl; f.close(); return EXCEPTION_CONTINUE_SEARCH; } int _tmain(int argc, _TCHAR* argv[]) { AddVectoredExceptionHandler(1, VectoredExceptionHandler); SetUnhandledExceptionFilter(TopLevelExceptionHandler); // Exception code c0000374 int* p2 = new int; delete p2; delete p2; // Exception code c0000005 int* p1 = NULL; *p1 = 99; return 0; }

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  • Reference to undeclared entity 'nbsp' - why?

    - by Charles
    I have the following line of code: XDocument formConfiguration = XDocument.Load(ConfigurationManager.AppSettings["XMLFileURL"]); I get the following exception message: Reference to undeclared entity 'nbsp' There are no   sequences in the XML. There are no "&" characters in the XML. Where could this be coming from? Thanks, Charles

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  • Why FontStretch does not work in WPF?

    - by marco.ragogna
    I am trying setting FontStretch property on a TextBlock in WPF but it seems that it does not work. I tried Expanded, Condensed, etc. but the text appearance does not change. I am working on Windows XP with Framework 4.0 and tested both with Verdana and Arial. Does it work only on Windows 7 or only with some specific fonts?

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