Search Results

Search found 66 results on 3 pages for 'skydoor'.

Page 2/3 | < Previous Page | 1 2 3  | Next Page >

• The question regarding cerr cout and clog

  - by skydoor

  Can anybody explain the difference between cerr cout and clog and why does different objects are proposed? I know the differences are as below: 1) cout can redirected but cerr can't 2) clog can use buffer. I am confused about the point 2, I am grateful if anybody can elaborate it more.

  Read the article

• Can destructor be declared as pure virtual?

  - by skydoor

  I know that the destructor can be virtual, how about pure virtual? if yes, what's the usage? If not, what's the error, compile error or runtime error?

  Read the article

• Where is pure virtual function located in C++?

  - by skydoor

  Which virtual table will be pure virtual function located? In the base class or derived class? For example, what does the virtual table look like in each class? class Base { virtual void f() =0; virtual void g(); } class Derived: public Base{ virtual void f(); virtual void g(); }

  Read the article

• How to return a string literal from a function

  - by skydoor

  Hi I am always confused about return a string literal or a string from a function. I was told that there might be memory leak because you don't know when the memory will be deleted? For example, in the code below, how to implement foo() so that make the output of the code is "Hello World"? void foo ( ) // you can add parameters here. { } int main () { char *c; foo ( ); printf ("%s",c); return 0; } Also if the return type of foo() is not void, but you can return char*, what should it be.

  Read the article

• some qeustions about Vector in STL

  - by skydoor

  I have some questions about vector in STL to clarify..... 1 Where are the objects in vector allocated? heap? 2 does vector have boundary check? If the index out of the boundary, what error will happen? 3 Why array is faster than vector? 4 Is there any case in which vector is not applicable but array is a must?

  Read the article

• How often will a programmer be asked to write a makefile file?

  - by skydoor

  Is makefile an advanced problem or a general problem for a programmer? For a C++ programmer, how often will he be asked to write a makefile file?

  Read the article

• memset for initialization in C++

  - by skydoor

  memset is sometimes used to initialize data in a constructor like the example below. Does it work in general ? Is it a good idea in general? class A { public: A(); private: int a; float f; char str[35]; long *lp; }; A::A() { memset(this, 0, sizeof(*this)); }

  Read the article

• How to implement pure virtual function in C++

  - by skydoor

  Hi, I think the implementation of virtual function is talked about a lot. My question is what about pure virtual function? However it is implemented? In virtual table, how to tell it is a pure or non-pure? What the difference between pure virtual function and virtual function with implementation?

  Read the article

• How could one emulate namespace in C?

  - by skydoor

  In C++ one might use namespace to keep independent groups working in the same code base from inadvertently creating functions with the same name and thus creating a conflict. My question is, before the idea of namespace comes out, how might one emulate namespace in C.

  Read the article

• Why friend function is preferred to member function for operator<<

  - by skydoor

  When you are going to print an object, a friend operator<< is used. Can we use member function for operator<< ? class A { public: void operator<<(ostream& i) { i<<"Member function";} friend ostream& operator<<(ostream& i, A& a) { i<<"operator<<"; return i;} }; int main () { A a; A b; A c; cout<<a<<b<<c<<endl; a<<cout; return 0; } One point is that friend function enable us to use it like this cout<<a<<b<<c What other reasons?

  Read the article

• How might one emulate polymorphism in C?

  - by skydoor

  Polymorphism is a key characteristic in C++, how might one emulate polymorphism in C?

  Read the article

• What's the usage if I provide an implementation for a pure virtual function in C++

  - by skydoor

  I know that it's OK for a pure virtual function to have an implementation. However, why it is like this? Is there conflict for the two concepts? What's the usage? Can any one offer any example?

  Read the article

• How to debug a running C++ program in Linux?

  - by skydoor

  Hi I have a question about debugging a running C++ program in Linux. If a programming is already running and can't be interrupted, how to do that. I can find three ways, but I don't know too much about details, I am grateful if any one can elaborate it deeper. 1) we can use GDB by specifying the process ID gdb -p PID In this case, what's the difference between this and attach PID? 2) We can use pstat, however, I am using Ubuntu, no pstat, but only mpstat it seems that mpstat does not provide too much information, and not so many options. 3) check the details information under directory ./proc In this case, just go to the directory with the PID. However, should this be done mannually?

  Read the article

• One question with array declaration in C++

  - by skydoor

  Hi What's the difference between the two code below. int a[] = {0,0}; int a[2] = {0,0}; It seems I can assign value to a[3] in both cases. I can access a[3] in any case. So what's the difference?

  Read the article

• why there is no find for vector in C++

  - by skydoor

  what's the alternative? Should I write by myself?

  Read the article

• What's the drawback to declare all the functions virtual in C++?

  - by skydoor

  Hi, If I am developing a class and I don't know who are going to use it. What's the drawback if I declare all the member functions virtual? It's a good design or bad design? Thanks so much! Regards.

  Read the article

• operator new and new operator, which can't be overloaded?

  - by skydoor

  It seems both can be overloaded, but somebody said not..... What's the case?

  Read the article

• Singleton pattern in C++

  - by skydoor

  I have a question about the singleton pattern. I saw two cases concerning the static member in the singleton class. First it is an object, like this class CMySingleton { public: static CMySingleton& Instance() { static CMySingleton singleton; return singleton; } // Other non-static member functions private: CMySingleton() {} // Private constructor ~CMySingleton() {} CMySingleton(const CMySingleton&); // Prevent copy-construction CMySingleton& operator=(const CMySingleton&); // Prevent assignment }; One is an pointer, like this class GlobalClass { int m_value; static GlobalClass *s_instance; GlobalClass(int v = 0) { m_value = v; } public: int get_value() { return m_value; } void set_value(int v) { m_value = v; } static GlobalClass *instance() { if (!s_instance) s_instance = new GlobalClass; return s_instance; } }; What's the difference between the two cases? Which one is correct?

  Read the article

• What's the case for duplications in BST?

  - by skydoor

  How to solve the problem with duplication in Binary Search Tree?

  Read the article

• What's the pros and cons of singleton in C++?

  - by skydoor

  I have some questions about singletons in C++. Under what situations is a singleton a must? What are the pros and cons of singletons? I was told they could cause memory leaks, how is that? I was also told that initialization is a problem, is that true?

  Read the article

• How can I sort the vector elements using members as the key in C++

  - by skydoor

  suppose we have a vector<student> allstudent Now I would like to sort the students using different memebers,such as name, age, address, like that. How can I do that?

  Read the article

• When pass-by-pointer is preferred to pass-by-reference in C++?

  - by skydoor

  I can imagine one case, in which the input parameter could be NULL so that pass-by-pointer is preferred but not pass-by-reference? Can anybody add more cases?

  Read the article

• Why the size of a pointer is 4bytes in C++

  - by skydoor

  Hi On the 32-bit machine, why the size of a pointer is 32-bit? Why not 16-bit or 64-bit? What's the cons and pros?

  Read the article

• how does sizeof work with array in C++

  - by skydoor

  Hi, I was told the array name is a pointer char a[] = "a" but when sizeof(a) = 2 why not it is a size of pointer here? however when I define it like this char* a ="a"; we get sizeof(a) =4; Well, I think I need more information about how does sizeof work with the array names.... Can anyone elaborate that?

  Read the article

• Why can't one ctor call another ctor to initialize the object

  - by skydoor

  class Foo { public: Foo() { Foo(1)} Foo(int x, int y = 0):i(x) {} private: int i; } Can anybody give me some reasonas about can I do this? If not why?

  Read the article

< Previous Page | 1 2 3  | Next Page >