In C, the amount of RAM a variable uses depends on its data type, not on the language itself. For example, char is typically 1 byte, int is often 2 or 4 bytes, float is usually 4 bytes, and double is usually 8 bytes.

How C uses memory

C automatically reserves memory for variables when the program is compiled, which is called static memory allocation, and it can also allocate memory at runtime using functions like malloc() or calloc(). The exact size of a type can vary by system, so the sizeof operator is the standard way to check it in your program.

Example

c

#include <stdio.h>

int main() {
    int x;
    printf("%zu\n", sizeof(x));
    return 0;
}

That prints the number of bytes used by x on your machine, which is the safest way to answer “how much RAM” a C type or variable uses.

If you meant system RAM

If you meant the total RAM installed on the computer from a C program, that is a different question. On Linux, one common approach is to read /proc/meminfo, while on Windows you can query system memory through operating-system APIs or WMI.