newdelete.cpp

#include <iostream>
using namespace std;

struct Student
{
    char name[4];
    int born;
    bool male; 
};

int main()
{
    //allocate an int, default initializer (do nothing)
    int * p1 = new int; 
    //allocate an int, initialized to 0
    int * p2 =  new int();
    //allocate an int, initialized to 5
    int * p3 =  new int(5); 
    //allocate an int, initialized to 0
    int * p4 =  new int{};//C++11    
    //allocate an int, initialized to 5
    int * p5 =  new int {5};//C++11

    //allocate a Student object, default initializer
    Student * ps1 = new Student;
    //allocate a Student object, initialize the members
    Student * ps2 = new Student {"Yu", 2020, 1}; //C++11

    //allocate 16 int, default initializer (do nothing) 
    int * pa1 = new int[16];
    //allocate 16 int, zero initialized 
    int * pa2 = new int[16]();
    //allocate 16 int, zero initialized 
    int * pa3 = new int[16]{}; //C++11
    //allocate 16 int, the first 3 element are initialized to 1,2,3, the rest 0
    int * pa4 = new int[16]{1,2,3}; //C++11

    //allocate memory for 16 Student objects, default initializer
    Student * psa1 = new Student[16];
    //allocate memory for 16 Student objects, the first two are explicitly initialized
    Student * psa2 = new Student[16]{{"Li", 2000,1}, {"Yu", 2001,1}}; //C++11
    cout << psa2[1].name << endl;
    cout << psa2[1].born << endl;

    //deallocate memory
    delete p1;
    //deallocate memory
    delete ps1;

    //deallocate the memory of the array
    delete pa1;
    //deallocate the memory of the array
    delete []pa2;

    //deallocate the memory of the array, and call the destructor of the first element
    delete psa1;
    //deallocate the memory of the array, and call the destructors of all the elements
    delete []psa2;

    return 0;
}