Why do we need the address of a variable?

Question

Look title.

Answer 1

Juan David Padilla Diaz In fact, you don't need a pointer in this case. This would work perfectly, with exactly the same result:

int x = 5;
int p = x;
cout << p; // Outputs 5

A pointer would be needed, for example, here:

void change_num (int *num) {
*num = 10;
}

int main () {
int x = 5;
change_num(x);
cout << x; // Outputs 10
return 0;
}

The function can only change the variable because it receives a pointer to its address, so it writes there.
If we send only the value - like in change_num(int num) - the function could change the number, but not the variable which has the number in the main function. change_num needs to know where to write.

Answer 2

I will use this example to explain you.
int x = 5;
int *p = x;
cout<<p;
output:
error, because the conversion of int to int*(pointer) cant be done like that because it's different.
So if we want to store a value in a pointer from another variable we need the address of the value that we want to store in memory, so we use an address to tell to the pointer that the value we want to store from another variable it's located in the following address so it can be stored.
int x = 5;
int *p =&x://address to the value
cout<<*p;
output :
5

Answer 3

To send it to functions so they can change the variable value