Most viewed questions in C++

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How to end C++ code

I want my C++ code to terminate  ...READ MORE

Aug 17, 2022 in C++ by Nicholas
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What is object slicing?

What is object slicing in C++ and ...READ MORE

Jul 13, 2022 in C++ by Nicholas
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What is the C++ function to raise a number to a power?

What's the best way to raise a n ...READ MORE

Jun 1, 2022 in C++ by Nicholas
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774 views
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functions in c++ call by value and call by reference

The code below shows how to call a function in both methods.  Please explain the major differences or meanings of call by value and call by reference to me.  1.Make a value-based call.  2.Call based on a reference.  The call by value method is demonstrated in the following code. In a comment, I expressed my reservations. #include<iostream> int main(){ void change(int);//why function prototype is before ...READ MORE

Jun 6, 2022 in C++ by Nicholas
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C++ "Object" class

No, there is no generic base class&nb ...READ MORE

Jun 2, 2022 in C++ by Damon
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772 views
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How to choose between map and unordered_map?

Assume I wanted to map data that ...READ MORE

Jul 4, 2022 in C++ by Nicholas
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767 views
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dynamic_cast and static_cast in C++

 I'm perplexed by the dynamic cast keyword in C++. struct A { virtual ...READ MORE

Jul 15, 2022 in C++ by Nicholas
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Explanation of function pointers

It's a little perplexing. Function type and pointer to function type are distinct kinds (no more similar than int and pointer to int).  However, in virtually all cases, a function type decays to a reference to a function type.  In this context, rotting roughly refers to conversion (there is a difference between type conversion and decaying, but you are probably not interested in it right now). What matters is that practically every time you use a function type, you end up with a reference to the function type.  But take note of the nearly - almost every time is not always! And there are rare circumstances where it does not. typedef void(functionPtr)(int); functionPtr fun = function; This code tries to clone one function to another (not the pointer! the function!)  However, this is not feasible since functions in C++ cannot be copied.  The compiler does not let this, and I'm surprised you got it compiled (you say you got linker errors?) Now for the code: typedef void(functionPtr)(int); functionPtr function; function(5); function does ...READ MORE

Jun 21, 2022 in C++ by Damon
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761 views
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What is a smart pointer and when should I use one?

A smart pointer is similar to a ...READ MORE

Jun 2, 2022 in C++ by Damon
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758 views
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Examples of good gotos in C or C++

Here's one method I've heard of folks use. But I've never seen it in the wild.  And that only pertains to C since RAII allows you to accomplish this more idiomatically in C++. void foo() { if (!doA()) ...READ MORE

Aug 2, 2022 in C++ by Damon
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Are virtual functions the only way to achieve Runtime Polymorphism in C++?

fprintf is a polymorphism function in the C programming language. It can print to a file, stdout, a printer, a socket, or whatever else the system can represent as a stream if you supply it different handles. FILE* file = fopen("output.txt", "w"); ...READ MORE

Jun 21, 2022 in C++ by Damon
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What are the differences between a pointer variable and a reference variable?

What distinguishes a reference variable from a ...READ MORE

Jul 11, 2022 in C++ by Nicholas
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751 views
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Selection sort in C++ (modified) not working for all cases

I was attempting to tweak the selection sort code in C++ in order to test the results.  My updated code is as follows: #include<bits/stdc++.h> using namespace std; int main() { ...READ MORE

Jun 29, 2022 in C++ by Damon
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740 views
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1 answer

The new syntax "= default" in C++11

A defaulted default function Object() { [native code] } is defined as a user-defined default function Object() { [native code] } with an empty compound statement and no initialization list. I'll give you an example to demonstrate the difference: #include <iostream> using namespace std; class A { public: ...READ MORE

Jun 7, 2022 in C++ by Damon
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"We do not use C++ exceptions" — What's the alternative? Let it crash?

If you don't utilise exceptions, by definition, ...READ MORE

Aug 2, 2022 in C++ by Damon
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735 views
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not able to run graphics in DEV C++

Unable to run the graphics from following ...READ MORE

Jul 15, 2022 in C++ by Nicholas
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735 views
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take string input using char* in C and C++

I'm having trouble accepting a string (actually a character array) as input.  Consider the following declaration: char* s; I have to input a string ...READ MORE

Jul 1, 2022 in C++ by Nicholas
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734 views
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Use of "this" keyword in C++ [duplicate]

Yes, it is optional and generally omitted.  However, it may be essential for accessing variables after they have been overridden in the scope: Person::Person() { int age; ...READ MORE

Jun 20, 2022 in C++ by Damon
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How do I declare a 2d array in C++ using new?

How do I declare a two-dimensional array using new? For example, for a "typical" array, I would:      int* ary = new int[Size] but int** ...READ MORE

Jul 15, 2022 in C++ by Nicholas
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730 views
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What is the difference between a concrete class and an abstract class?

I'm learning C++, but I'm having trouble ...READ MORE

Jul 26, 2022 in C++ by Nicholas
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727 views
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How to use the priority queue STL for objects?

class Person { public: int age; }; I'd want to put objects of the type Person in a priority queue. priority_queue< ...READ MORE

Jun 27, 2022 in C++ by Nicholas
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723 views
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What is a lambda expression in C++11?

In C++11, what is a lambda expression? A: It's the object of an autogenerated class with overloading operator() const under the hood.  Closure is a type of object that is produced by the compiler.  This 'closure' idea is similar to C++11's bind notion.  Lambdas, on the other hand, usually produce better code.  Full inlining is also possible with calls through closures. Q: When do you think I'd utilise one? A: Define "simple and tiny logic" and request that the compiler generate the code from the preceding question.  You tell the compiler the expressions you wish to be inside the operator ().  The compiler will produce everything else for you. Q: What kind of problem do they tackle that couldn't be solved before they were introduced? A: It's some form of syntactic sugar, like using operators instead of functions for custom add, subtract, and other operations... However, wrapping 1-3 lines of genuine logic to some classes, and so on, saves additional lines of needless code!  Some engineers believe that if the number of lines is reduced, there is a lower likelihood of mistakes (which I agree with). Example of usage auto x = [=](int arg1){printf("%i", ...READ MORE

Jun 15, 2022 in C++ by Damon
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Difference between set.upper_bound() and upper_bound(set.begin(), set.end()) stl

I discovered that set.upper bound() was quicker ...READ MORE

Jun 29, 2022 in C++ by Damon
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709 views
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Default inheritance access specifier

If I have two classes A and ...READ MORE

Jul 22, 2022 in C++ by Nicholas
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703 views
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Differences between C++ string == and compare()?

I just read some recommendations on using std::string ...READ MORE

Jul 7, 2022 in C++ by Nicholas
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702 views
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Is the std::set iteration order always ascending according to the C++ specification?

According to what I've read, std::set in ...READ MORE

Jun 29, 2022 in C++ by Nicholas
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701 views
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Why aren't cmath's pow and sqrt templates?

I'm curious as to why std::sqrt and ...READ MORE

Jul 13, 2022 in C++ by Nicholas
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699 views
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C++ pointer to objects

Is it always necessary in C++ to  ...READ MORE

Jun 27, 2022 in C++ by Nicholas
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696 views
0 votes
0 answers

How to code a modulo (%) operator in C/C++/Obj-C that handles negative numbers

As a mathematician, one of my pet peeves of C-derived languages is : (-1) % 8 // comes out as ...READ MORE

Jul 27, 2022 in C++ by Nicholas
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691 views
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Why was the ampersand chosen as the symbol for references in C++?

Does anyone know why the ampersand was ...READ MORE

Aug 16, 2022 in C++ by Nicholas
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689 views
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C++ printing boolean, what is displayed?

I print a bool to an output stream like ...READ MORE

Jul 1, 2022 in C++ by Nicholas
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687 views
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C++ Singleton design pattern

I recently came upon a C++ realization/implementation of the Singleton design pattern.  It looked like this (I took it from a real-life example): // a lot of methods are omitted ...READ MORE

Jul 4, 2022 in C++ by Nicholas
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685 views
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Why do we use volatile keyword?

I've never used it, but I'm curious ...READ MORE

Jul 25, 2022 in C++ by Nicholas
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681 views
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What does the C++ standard state the size of int, long type to be?

I'm seeking for specific information on the sizes of basic C++ types.  I understand that it is determined by the architecture (16 bits, 32 bits, or 64 bits) and the compiler. But are there any C++ standards? On a 32-bit architecture, I'm using Visual Studio 2008.  This is what I get: char : 1 byte short : 2 ...READ MORE

Jul 5, 2022 in C++ by Nicholas
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677 views
0 votes
1 answer

What is the name of the "<<" and ">>" operators? [duplicate]

This operator (<<) applied to an output ...READ MORE

Jun 20, 2022 in C++ by Damon
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675 views
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What are access specifiers? Should I inherit with private, protected or public?

I'm not sure what access modifiers signify ...READ MORE

Jul 22, 2022 in C++ by Nicholas
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665 views
+1 vote
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Using push_back vs at in a vector in C++

I'm not sure how to use vectors in C++.  It has to do with the vector's push back technique.  I used push back to insert entries into the vector in the first programme.  I used at() to insert entries into the vector in the second application. #include <iostream> #include <vector> #include <string> using namespace std; int main ...READ MORE

Jul 22, 2022 in C++ by Nicholas
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664 views
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Constructor Overloading in C++

In your function Object() { [native code] }, Node(Game(),v); does not work as expected.  It simply creates a temporary without actually using it, and has no effect.  When control passes over the ;, it immediately destroys the temporary. Initializing the members in each function Object() { [native code] } is the correct way to go.  You could put their shared code in a private init() member function and call it from each function Object() { [native code] }, as shown below: class Foo { public: ...READ MORE

Jun 21, 2022 in C++ by Damon
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664 views
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Simple C++ swap function

Why is it that if I have a method like this to swap two numbers, it doesn't work[swap], (I know I can accomplish this by defining pointers in the prototype and then passing the addresses of the relevant variables in main()), yet it works for arrays without having to supply pointers and addresses? It does not work. void num_exchange(int m, int n); int main(){ int num1 ...READ MORE

Jul 27, 2022 in C++ by Nicholas
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661 views
0 votes
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Sorting Characters Of A C++ String

Is there a built-in method for sorting characters in a string, or do I have to construct my own? for instance: string word = "dabc"; I would want to ...READ MORE

Jun 27, 2022 in C++ by Nicholas
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657 views
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How come an array's address is equal to its value in C?

The pointer values and pointer addresses in ...READ MORE

Aug 8, 2022 in C++ by krishna
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656 views
0 votes
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What type of members can I add in a c++ abstract class

Hello, let's say I have an abstract class with a few pure abstract functions and a few classes that derive from it, and all of the data from these classes eventually becomes similar, I was wondering if it would be wise, or even possible, to declare a vector under protected in the abstract class to collect the data so something like that. class A { protected: vector <string> ...READ MORE

Jul 27, 2022 in C++ by Nicholas
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654 views
0 votes
1 answer

C++ multiset, return key at position?

A set (or multiset) is typically represented ...READ MORE

Jun 27, 2022 in C++ by Damon
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648 views
0 votes
0 answers

What is a stream in C++?

I've been hearing a lot about streams, ...READ MORE

Aug 11, 2022 in C++ by Nicholas
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636 views
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memory allocation for objects

When we instantiate a variable in C++, ...READ MORE

Aug 11, 2022 in C++ by Nicholas
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635 views
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Inbuilt __gcd(A,B) function in C++

I recently learned about a c++ specia ...READ MORE

Jul 11, 2022 in C++ by Nicholas
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634 views
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throwing a run time error

I just started Programming: Principles and Practice Using C++ because I'm new to programming.  Errors and how to handle them are covered in one of the chapters. What I'm attempting to implement is this little line of code.  The programme will end with a system error message and the text we gave as a parameter, according to the book's description of error(). #include <iostream> #include <string> using namespace std; int area (int ...READ MORE

Jul 13, 2022 in C++ by Nicholas
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633 views
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Visual C++ vs Visual C# , which is the best to learn?

I completed my C++ lessons and practises ...READ MORE

Jul 22, 2022 in C++ by Nicholas
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626 views
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How member functions are implemented in C++?

I read somewhere that member functions in C++ are similar to regular functions but with an additional implicit this parameter. As a result, I assumed that this software would be unable to discriminate between two functions.  However, the software executed successfully.  So, was the above statement incorrect? #include <iostream> class MyCls { ...READ MORE

Jul 22, 2022 in C++ by Nicholas
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624 views
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What is the STL?

I'm not a C++ coder, thus I ...READ MORE

Jun 29, 2022 in C++ by Damon
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618 views