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  • What is the result of this SQL query?

    - by Martin
    I'm working on a mock exam paper at the moment, however I have no set of correct answers and I'm not sure what the correct answer of this SQL query is. Given a table: foo, bar a , 1 b , 3 a , 2 c , 1 and the query: SELECT foo, sum(bar) FROM table GROUP BY foo The two ways I can see this going are either: a 3 a 3 b 3 c 1 or a 3 b 3 c 1 Thanks.

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  • binary operator "<"

    - by md004
    Consider this expression as a "selection" control structure on integer "x": 0 < x < 10, with the intention that the structure returns TRUE if "x" is in the range 1..9. Explain why a compiler should not accept this expression. (In particular, what are the issues regarding the binary operator "<"? Explain how a prefix operator could be introduced so the expression can be successfully processed.

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  • IE8 error when using dyanamic form actions

    - by user330711
    Hello all: Please go here to see an iframe based web app. Click on the map of Australia, choose a city, then buy some tickets. Now you will see the cart form located on the lower right corner. The problem is in IE8, I cannot delete checked rows from the table; whereas in other browsers such as FireFox3.6, Opera10, Safari4 and Chrome4, this action is all right. Below is the related javascript. It doesn't use jQuery, as part of the requirement is no framework allowed! And iframes are the my best bet, ajax will simply kill me under this restriction. /* cartForm.js */ function toDeleteRoutes() //this function is executed before form is to be submitted. { if(document.getElementsByClassName('delete_box').length > 0) //there're rows to delete { document.getElementById('cartForm').action ="./deleteRoutes.php"; document.getElementById('cartForm').target ="section4"; return true; //this enables the form to be submitted as usual. } else return false; //there is no more row in table to delete! } function toSendEmail() //this function is executed before form is to be submitted. { document.getElementById('cartForm').action ="./sendEmail.php"; document.getElementById('cartForm').target ="section3"; document.getElementById('delete_btn').disabled = true; //disable delete button now return true; //this enables the form to be submitted as usual. } function toCancelPurchase() { document.getElementById('cartForm').action ="./cancelPurchase.php"; document.getElementById('cartForm').target ="section4"; return true; //this enables the form to be submitted as usual. } I don't know which part is wrong, or this is just because IE8 screws all?

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  • question about function derivatives

    - by davit-datuashvili
    hi i have question for example i have some function int sumefunction(//parameters here let say int x){ return something let say x*x+2*x+3 or does not matter } i am interesting how find derivative of this function ?if i have int f(int x){ return sin(x); } after derivative it must return cos(x) thanks

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  • C++ Problem resolution - is it the best way to simulate a "tuple"?

    - by fbin
    Hi everyone! I've got the following problem: "Write a template function vectorMAXMIN() that will accept a vector and a number indicating the size of the vector and will return the max and the min values of the vector"... So i think in it... Create a class vector to avoid the "size" passing value and control the insertions and can get from this the max and min values... ( dunno if it's a good idea ) The problem is "how to return a tuple?" When i read the problem, i thought in a tuple to return "max, min values" is it correct? The code: #include <iostream> template < typename T > class _tuple { public: T _Max; T _Min; }; template < typename T > class _vector { public: _vector( int cnt = 0); ~_vector(); _tuple< T > get_tuple( void ); void insert( const T ); private: T *ptr; int cnt; int MAX; }; template < typename T > _vector< T >::_vector( int N ) { ptr = new T [N] ; MAX = N; cnt = 0; } template < typename T > _tuple<T> _vector< T >::get_tuple( void ) { _tuple< T > _mytuple; _mytuple._Max = ptr[0]; _mytuple._Min = ptr[0]; for( int i = 1; i < cnt; i++) { if( _mytuple._Max > ptr[i] ) _mytuple._Max = ptr[i]; if( _mytuple._Min < ptr[i] ) _mytuple._Min = ptr[i]; } return _mytuple; } template < typename T > void _vector< T >::insert( const T element) { if( cnt == MAX ) std::cerr << "Error: Out of range!" << std::endl; else { ptr[cnt] = element; cnt++; } } template < typename T > _vector< T >::~_vector() { delete [] ptr; } int main() { _vector< int > v; _tuple < int > t; v.insert(2); v.insert(1); v.insert(5); v.insert(0); v.insert(4); t = v.get_tuple(); std::cout << "MAX:" << t._Max; std::cout << " MIN:" << t._Min; return 0; }

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  • C: theory on how to extract files from an archived file

    - by donok
    In C I have created a program which can archive multiple files into an archive file via the command line. e.g. $echo 'file1/2' > file1/2.txt $./archive file1.txt file2.txt arhivedfile $cat archivedfile file1 file2 How do I create a process so that in my archivedfile I have: header file1 end header file2 end They are all stored in the archive file one after another after another. I know that perhaps a header file is needed(containing filename, size of filename, start and end of file) for extracting these files back out into their original form, but how would I go about doing this. I am stuck on where and how to start. Please could someone help me on some logic as to how to approach extracting files back out of an archived file.

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  • How do I get a array to just count how many numbers there are instead of counting the value of each number?

    - by Chad Loos
    //This is the output of the program *** start of 276 2D Arrays_03.cpp program *** Number Count Total 1 3 3 2 6 9 3 15 24 4 6 30 5 9 39 *** end of 276 2D Arrays_03.cpp program *** #include <iostream> #include <string> #include <iomanip> using namespace std; const int COLUMN_SIZE = 13; int main(void) { const int ROW_SIZE = 3; const int COUNT_SIZE = 5; void countValues(const int[][COLUMN_SIZE], const int, int[]); void display(const int [], const int); int numbers[ROW_SIZE][COLUMN_SIZE] = {{1, 3, 4, 5, 3, 2, 3, 5, 3, 4, 5, 3, 2}, {2, 1, 3, 4, 5, 3, 2, 3, 5, 3, 4, 5, 3}, {3, 4, 5, 3, 2, 1, 3, 4, 5, 3, 2, 3, 5}}; int counts[COUNT_SIZE] = {0}; string choice; cout << "*** start of 276 2D Arrays_03.cpp program ***" << endl; cout << endl; countValues(numbers, ROW_SIZE, counts); display(counts, COUNT_SIZE); cout << endl; cout << endl; cout << "*** end of 276 2D Arrays_03.cpp program ***" << endl << endl; cin.get(); return 0; } // end main() This is the function where I need to count each of the values. I know how to sum rows and cols, but I'm not quite sure of the code to just tally the values themselves. void countValues(const int numbers[][COLUMN_SIZE], const int ROW_SIZE, int counts[]) This is what I have so far. { for (int index = 0; index < ROW_SIZE; index++) counts[index]; {

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  • Postfix evaluation in C

    - by Andrewziac
    I’m taking a course in C and we have to make a program for the classic Postfix evaluation problem. Now, I’ve already completed this problem in java, so I know that we have to use a stack to push the numbers into, then pop them when we get an operator, I think I’m fine with all of that stuff. The problem I have been having is scanning the postfix expression in C. In java it was easier because you could use charAt and you could use the parseInt command. However, I’m not aware of any similar commands in C. So could anyone explain a method to read each value from a string in the form: 4 9 * 0 - = Where the equals is the signal of the end of the input. Any help would be greatly appreciated and thank you in advance :)

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  • How to lock serialization in java?

    - by PaulP89
    I am just starting with JAVA serialization, I have one exercise to do and I need to lock serialization on any class, it is suppose to throw an exception when I attempt to serialize that class. Does anyone know how to do it? Thank you

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  • Problems Expanding an Array in C++

    - by dxq
    I'm writing a simulation for class, and part of it involves the reproduction of organisms. My organisms are kept in an array, and I need to increase the size of the array when they reproduce. Because I have multiple classes for multiple organisms, I used a template: template <class orgType> void expandarray(orgType* oldarray, int& numitems, int reproductioncount) { orgType *newarray = new orgType[numitems+reproductioncount]; for (int i=0; i<numitems; i++) { newarray[i] = oldarray[i]; } numitems += reproductioncount; delete[] oldarray; oldarray = newarray; newarray = NULL; } However, this template seems to be somehow corrupting my data. I can run the program fine without reproduction (commenting out the calls to expandarray), but calling this function causes my program to crash. The program does not crash DURING the expandarray function, but crashes on access violation later on. I've written functions to expand an array hundreds of times, and I have no idea what I screwed up this time. Is there something blatantly wrong in my function? Does it look right to you? EDIT: Thanks for everyone's help. I can't believe I missed something so obvious. In response to using std::vector: we haven't discussed it in class yet, and as silly as it seems, I need to write code using the methods we've been taught.

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  • joining two tables and getting aggregate data

    - by alex
    how do i write a query that returns aggregate sales data for California in the past x months. ----------------------- ----------------------- | order | | customer | |-----------------------| |-----------------------| | orderId int | | customerId int | | customerId int | | state varchar | | deposit decimal | ----------------------- | orderDate date | ----------------------- ----------------------- | orderItem | |-----------------------| | orderId int | | itemId int | | qty int | | lineTotal decimal | | itemPrice decimal | -----------------------

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  • Opening a file with a variable as name and checking for undefined values

    - by Harm De Weirdt
    I'm having some problems writing data into a file using Perl. sub startNewOrder{ my $name = makeUniqueFileName(); open (ORDER, ">$name.txt") or die "can't open file: $!\n"; format ORDER_TOP = PRODUCT<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<CODE<<<<<<<<AANTAL<<<<EENHEIDSPRIJS<<<<<<TOTAAL<<<<<<< . format ORDER = @<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< @<<<<<<<< @<<<< @<<<<<< @<<<<< $title, $code, $amount, $price, $total . close (ORDER); } This is the sub I use to make the file. (I translated most of it.) The makeUniqueFileName method makes a fileName based upon current time("minuteshoursdayOrder"). The problem now is that I have to write to this file in another sub. sub addToOrder{ print "give productcode:"; $code = <STDIN>; chop $code; print "Give amount:"; $amount = <STDIN>; chop $amount; if($inventory{$code} eq undef){ #Does the product exist? print "This product does not exist"; }elsif($inventory{$code}[2] < $amount && !defined($inventaris{$code}[2]) ){ #Is there enough in the inventory? print "There is not enough in stock" }else{ $inventory{$code}[2] -= $amount; #write in order file open (ORDER ">>$naam.txt") or die "can't open file: $!\n"; $title = $inventory{$code}[0]; $code = $code; $amount = $inventory{$code}[2]; $price = $inventory{$code}[1]; $total = $inventory{$code}[1]; write; close(ORDER); } %inventory is a hashtable that has the productcode as key and an array with the title, price and amount as value. There are two problems here: when I enter an invalid product number, I still have to enter an amount even while my code says it should print the error directly after checking if there is a product with the given code. The second problem is that the writing doesn't seem to work. It always give's a "No such file or directory" error. Is there a way to open the ORDER file I made in the first sub without having to make $name not local? Or just a way to write in this file? I really don't know how to start here. I can't really find much info on writing a file that has been closed before, and in a different sub. Any help is appreciated, Harm

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  • how can I create macro definitions for the lines commented in the code.

    - by yaprak
    #include <stdio.h> //Here use a macro definition that assigns a value to SIZE (for example 5) int main() { int i; int array[SIZE]; int sum=0; for(i=0; i<SIZE; i++) { //Here use a macro definition named as CALCSUM to make the //following addition operation for the array printf("Enter a[%d] = ",i); scanf("%d", &array[i]); sum+=array[i]; //Here use a macro definition named as VERBOSE to print //what program does to the screen printf("The user entered %d\n", array[i]); // // //If the macro definition CALCSUM is not used, the program //should assign 0 to the i-th element of the array array[i]=0; //Here, again use VERBOSE to print what program does to the screen printf("a[%d] is assigned to zero\n", i); // // } //If CALCSUM is defined, print the summation of the array elements to the screen printf("Summation of the array is %d\n",sum); // //If CALCSUM is not defined, but VERBOSE mode is used, print the following printf("All the elements in the array are assigned to zero\n"); // printf("Program terminated\n"); return 0; } When CALCSUM is defined, the program will sum up the values of each element in the given array. If CALCSUM is not defined, each array element will be assigned to zero. Besides, when VERBOSE mode is defined, the program will make print statements pointed out active. [root@linux55]# gcc code.c [root@linux55]# ./a.out Program terminated [root@linux55]# gcc code.c -D CALCSUM [root@linux55]# ./a.out Enter a[0] = 3 Enter a[1] = 0 Enter a[2] = 2 Enter a[3] = 5 Enter a[4] = 9 Summation of the array is 19 Program terminated [root@linux55]# gcc code.c -D CALCSUM -D VERBOSE [root@linux55]# ./a.out Enter a[0] = 2 The user entered 2 Enter a[1] = 10 The user entered 10 Enter a[2] = 3 The user entered 3 Enter a[3] = 8 The user entered 8 Enter a[4] = 1 The user entered 1 Summation of the array is 24 Program terminated [root@linux55]# gcc code.c -D VERBOSE [root@linux55]# ./a.out a[0] is assigned to 0 a[1] is assigned to 0 a[2] is assigned to 0 a[3] is assigned to 0 a[4] is assigned to 0 All the elements in the array is assigned to zero Program terminated

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  • Question about permute-by-sorting

    - by davit-datuashvili
    In the book "Introduction to Algorithms", second edition, there is the following problem: Suppose we have some array: int a[] = {1,2,3,4} and some random priorities array: P = {36,3,97,19} and the goal is to permute the array a randomly using this priorities array. This is the pseudo code: PERMUTE-BY-SORTING (A) 1 n ? length[A] 2 for i ? 1 to n 3 do P[i] = RANDOM (1, n 3) 4 sort A, using P as sort keys 5 return A The result should be the permuted array: B={2, 4, 1, 3}; I have written this code: import java.util.*; public class Permute { public static void main (String[] args) { Random r = new Random(); int a[] = new int[] {1,2,3,4}; int n = a.length; int b[] = new int[a.length]; int p[] = new int[a.length]; for (int i=0; i<p.length; i++) { p[i] = r.nextInt(n*n*n) + 1; } // for (int i=0;i<p.length;i++){ // System.out.println(p[i]); //} } } How do I continue?

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  • How do I use requestFocus in a Java JFrame GUI?

    - by JohnWong
    I am given an assignment but I am totally new to Java (I have been programming in C++ and Python for two years). So we are doing GUI and basically we extended JFrame and added a couple fields. Say we have a field named "Text 1" and "Text 2". When user presses enter with the cursor in Text 1, move the focus to Text 2. I tried to add private JTextField textfield1() { textfield1 = new JTextField(); textfield1.setPreferredSize(new Dimension(200, 20)); textfield1.addActionListener( new ActionListener() { public void actionPerformed(ActionEvent e) { textfield1text = textfield1.getText().trim(); textfield1.setText(textfield1text); System.out.println(textfield1text); textfield1.requestFocus(); } }); return textfield1; } But that doesn't work at all. I noticed that requestFocus is not recommended, and instead one should use requestFocusWindows. But I tried that too. Upon some readings it seems like I have to do keyboard action and listener? But my teacher said it only requires 1 line...

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  • python-wordmatching

    - by challarao
    Write two functions, called countSubStringMatch and countSubStringMatchRecursive that take two arguments, a key string and a target string. These functions iteratively and recursively count the number of instances of the key in the target string. You should complete definitions for def countSubStringMatch(target,key): and def countSubStringMatchRecursive (target, key): For the remaining problems, we are going to explore other substring matching ideas. These problems can be solved with either an iterative function or a recursive one. You are welcome to use either approach, though you may find iterative approaches more intuitive in these cases of matching linear structures.

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  • PHP: Display comma after each element except the last. Using 'for' statement and no 'implode/explode

    - by Jonathan
    hi, so I have this simple for loop to echo an array: for ($i = 0; $i < count($director); $i++) { echo '<a href="person.php?id='.$director[$i]["id"].'">'.$director[$i]["name"].'</a>'; } The problem here is that when more than one element is in the array then I get everything echoed without any space between. I want to separate each element with a comma except the last one. I cant use 'implode' so I'm looking for another solution... Anyone?

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  • Need an algorithm for this problem

    - by Heisenburgor
    There are two integer sequences A[] and B[] of length N,both unsorted. Requirement: through the swapping of elements between A[] and B[], make the difference between {the sum of all elements in A[]} and {the sum of all elements in B[]} to be minimum. Many thanks

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  • Why does this program stop running?

    - by designloper
    Hi everyone....I am developing a card making system...nothing fancy. Right got this far but program now stops running with no error when running after the first card sample i.e. " Enter 'OK' if this card is OK, otherwise enter an alternative border character: + ". Any suggestions Java Masters? //Ask user for input //makes use of print line method System.out.println("Enter name: "); //took the variables //called the object of the scanner 'cardOrder' //and use the Scanner objects method '.nextLine' //to read the next line of the input firstName = cardOrder.nextLine(); mInitial = cardOrder.nextLine(); lastName = cardOrder.nextLine(); //Print out the "Here is a sample card" + the first name, middle initial and last name System.out.println("Here is a sample card: \n\n" + firstName + mInitial + lastName + "**************" + "**************" + firstName + mInitial + lastName + "\n* *" + "\n*" + " " + firstName + mInitial + lastName + " *" + "\n* *\n" + firstName + mInitial + lastName +"**************" + "**************" + firstName + mInitial + lastName + "\n"); //Ask user is the card is OK to proceed to order query or if they want an alternative border character: + System.out.println("Enter 'OK' if this card is OK, otherwise enter an alternative border character: + "); //Check if user entered "OK" and store it in var optionA optionA = cardOrder.nextLine(); //test if (a == optionA){ System.out.println("\nHow many cards would you like? "); cardsOrdered = cardOrder.nextInt(); equals = (int) (cardPriceA * cardsOrdered); System.out.println("The price of " + cardsOrdered + " cards"+ " is £" + equals + ".\n"); System.out.println("No Discount given."); } else if(b == optionA) { //Print out the "Here is a sample card" + the first name, middle initial and last name System.out.println("Here is a sample card: \n\n" + firstName + mInitial + lastName + "++++++++++++++" + "++++++++++++++" + firstName + mInitial + lastName + "\n+ +" + "\n+" + " " + firstName + mInitial + lastName + " +" + "\n+ +\n" + firstName + mInitial + lastName +"++++++++++++++" + "++++++++++++++" + firstName + mInitial + lastName + "\n"); //Ask user is the card is OK to proceed to order query or if they want an alternative border character: + System.out.println("Enter 'OK' if this card is OK, otherwise enter an alternative border character: OK "); //Check if user entered "OK" and store it in var optionA optionA = cardOrder.nextLine(); if (a == optionA){ System.out.println("\nHow many cards would you like? "); cardsOrdered = cardOrder.nextInt(); equals = (int) (cardPriceA * cardsOrdered); System.out.println("The price of " + cardsOrdered + " cards"+ " is £" + equals + ".\n"); System.out.println("No Discount given."); } } else if (c == optionA) {//Print out the "Here is a sample card" + the first name, middle initial and last name System.out.println("Here is a sample card: \n\n" + firstName + mInitial + lastName + "**************" + "**************" + firstName + mInitial + lastName + "\n* *" + "\n*" + " " + firstName + mInitial + lastName + " *" + "\n* *\n" + firstName + mInitial + lastName +"**************" + "**************" + firstName + mInitial + lastName + "\n"); //Ask user is the card is OK to proceed to order query or if they want an alternative border character: + System.out.println("Enter 'OK' if this card is OK, otherwise enter an alternative border character: + "); //Check if user entered "OK" and store it in var optionA optionA = cardOrder.nextLine(); if (a == optionA){ System.out.println("\nHow many cards would you like? "); cardsOrdered = cardOrder.nextInt(); equals = (int) (cardPriceA * cardsOrdered); System.out.println("The price of " + cardsOrdered + " cards"+ " is £" + equals + ".\n"); System.out.println("No Discount given."); } }

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  • need to read data from oracle database with many conditions

    - by randeepsp
    hi! i have 3 tables A,B and C. table A has column employee_name,id table B is the main table and has columns id,os version. table c has the columns id,package id and package version. i want to query the count of employee_name where the id of table a and c are matched with id of table b(which is the main table). i should also get the names of employees grouped by the os version they have and also the package version.

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