new-delete

#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;
}