Basic examples of pointers, the dereference operator, and the address of operator.

pointers.cpp

#include <iostream>

using namespace std;

int main()
{
    int num;

    cout << "The address of 'num': " << &num << endl;

    //Here, the '*' says numptr is a pointer that holds the address of an int
    int *numptr;

    numptr = &num;

    cout << "The address numptr is pointing to: " << numptr << endl;

    num = 12;

    cout << "The value of 'num': " << num << endl;

    //Here, the '*' dereferences numptr
    cout << "The value 'numptr' is pointing to: " << *numptr << endl;

    //We change the value at the address to 24
    *numptr = 24;

    cout << "The value 'numptr' is pointing to: " << *numptr << endl;
    cout << "The value of 'num': " << num << endl;

    char *my_char = new char;

    // TODO: Why doesn't this print out the address???
    cout << "The address my_char is pointing to: " << my_char << endl;

    *my_char = 'a';

    cout << "The value 'my_char' is pointing to: " << *my_char << endl;

    char *my_string = new char[7];

    my_string[1] = 'z';

    cout << "The second char of my_string is: " << my_string[1] << endl;

    *(my_string + 1) = 'x';

    // pointer points to an address e.g. 0x7ffd3520001c
    // When you add 1 to my_string, you increment that address
    // by 1 * sizeof(char);

    // In memory a char array looks like:
    // ____ ____ ____ ____ ____ ____ ____ ____
    // 0    1    2    3    4    5    6    7
    // my_string[1] == *(my_string + 1)
    // my_string[2] == *(my_string + 2)

    cout << "The second char of my_string is: " << *(my_string + 1) << endl;

    return 0;
}