The sizeof operator in C

main.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char* argv[]) {
    int a = 5;
    int arr[50] = { 3, 9, 10 }; // -> int*
    // size_t
    printf("%llu\n", sizeof(int));
    printf("%llu\n", sizeof(sizeof(int)));
    return 0;
}