Variables in memory

A variable of any type, can be seen as a data container. Being so, it occupies a certain space in the memory

Sizeof

Using the sizeof() operator, allows to know how much bytes the variable occupies. This, although standard in many computers for the primitive types, should not be assumed.

For example

#include<stdio.h>
int main(int argc, char const *argv[])
{
    int a;
    printf("int:%lu\n",sizeof(a));
}

Outputs:

int:4

Address operator

To know the memory address where the variable is store, the address operator & is used

For example

int a;
float b;
char c;

printf("a is located at %p\n",&a);
printf("b is located at %p\n",&b);
printf("c is located at %p.",&c);

prints

a is located at 000000000061FE1C
b is located at 000000000061FE18
c is located at 000000000061FE17.