The opaque pointer (pimpl) idiom has been inherited from C language where it is used to encapsulate implementation details. However, both old-school and "modern" C++ dispense you from writing some ugly code, and allow to use interfaces with object factories.

The example of implementation with both pimpl and interface approach …

How to extract all combinations (unordered subsets) from a given set in C++?

Let us estimate the count before. Suppose N is the size of a given set, and K is the number of elements in the subset. The count of all combinations (unordered subsets) of size K is

C …

Unlike Java or C#, the C++ world does not have a unified coding standard. The naming convention is still the choice of programmer teams or enterprises.

However, there are several standards widely used in the software industry.

• C++ standard library related code conventions
  • GCC Coding Conventions
  • ISO C++ coding standards …

Do not use static_cast when you cast from a basic class to a derived one. This may lead to undefined behavior. To handle the polymorphism, a virtual inheritance or a multiple inheritance case always use dynamic_cast instead.

The following short example shows the undefined behavior cases. This works with GCC …

Here we go. "The sleep of reason produces monsters"

Pros and cons

Why use Qt Test for unit testing and TDD (test-driven development)?

• small testing framework (about 6K lines of source code);
• seamless integration with QtCreator development environment;
• full support of Qt framework including classes/types and signal/slots;
• simple to start and use.

However, there are some drawbacks …

Context

Previously, comparing C++Builder classic and Clang compilers I regreted than CodeGuard tool doesn't work with Clang. Fortunately, there are other tools which can help you to profile program code and detect memory leaks. The Dataleaker is the one of these tools.

Installation

The installation requires local administrator rights …

Q1. Difference between ++*p, *p++ and *++p

Priority to keep in mind:

1. postfix ++
2. prefix ++
3. *

#include <stdio.h>
int main()
{
    int arr[] = {10, 20};
    int *p1 = arr;
    int *p2 = arr;
    int *p3 = arr;
    printf("arr[0] = %d, arr[1] = %d\n", arr[0], arr[1]);
    printf("arr[0] = %d, arr[1 …

Q1. Difference between ++*p, *p++ and *++p

Priority to keep in mind:

1. postfix ++
2. prefix ++
3. *

#include <stdio.h>
int main()
{
    int arr[] = {10, 20};
    int *p1 = arr;
    int *p2 = arr;
    int *p3 = arr;
    printf("arr[0] = %d, arr[1] = %d\n", arr[0], arr[1]);
    printf("arr[0] = %d, arr[1 …

According to specification, "...constructor is a special non-static member function of a class that is used to initialize objects of its class type". In addition to basic concepts, C++11 introduces move constructors, initializer list type and brace-enclosed lists of comma-separated initializers.

However the impact of introducing new constructors combining …