Answers for "constructor in c++ example"

constructor c++ struct

struct Rectangle {
    int width;  // member variable
    int height; // member variable

    // C++ constructors
    Rectangle()
    {
        width = 1;
        height = 1;
    }

    Rectangle( int width_  )
    {
        width = width_;
        height = width_ ;
    }

    Rectangle( int width_ , int height_ )
    {
        width = width_;
        height = height_;
    }
    // ...
};

C++ constructor

class Book {public:    Book(const char*);    ~Book();    void display();private:    char* name;};

constructor syntax in c++

struct S {
    int n;
    S(int); // constructor declaration
    S() : n(7) {} // constructor definition.
                  // ": n(7)" is the initializer list
                  // ": n(7) {}" is the function body
};
S::S(int x) : n{x} {} // constructor definition. ": n{x}" is the initializer list
int main()
{
    S s; // calls S::S()
    S s2(10); // calls S::S(int)
}