cpp class constructor

1class MyClass {     // The class
2  public:           // Access specifier
3    MyClass() {     // Constructor
4      cout << "Hello World!";
5    }
6};

1class MyClass {
2   public:
3      MyClass();  // This is the constructor
4   private:
5      int someInt;
6};
7
8MyClass::MyClass(void) {
9   someInt = 1;
10}

1struct S {
2    int n;
3    S(int); // constructor declaration
4    S() : n(7) {} // constructor definition.
5                  // ": n(7)" is the initializer list
6                  // ": n(7) {}" is the function body
7};
8S::S(int x) : n{x} {} // constructor definition. ": n{x}" is the initializer list
9int main()
10{
11    S s; // calls S::S()
12    S s2(10); // calls S::S(int)
13}

1class Book {public:    Book(const char*);    ~Book();    void display();private:    char* name;};