#include <stdio.h>

int main() {
    int a = 10;
    void *p = &a;

    // printing a through p
    printf("value of a is %d\n", *(int*)p);

    // setting a to 100 through p
    *(int*)p = 100;

    // printing the new value
    printf("new value of a is %d\n", *(int*)p);

    return 0;
}