#include <stdio.h>

// function prototypes
void callByValue(int a);
void callByPointer(int *a);

int main(int argc, char* argv[])
{
	int number;
    int *ptr;
    number = 8;
    ptr = &number;
    printf("number = %d\n", number);
    *ptr = 5;
    printf("number = %d\n", number);
    callByValue(number);
    printf("number = %d\n", number);
    callByPointer(&number);
    printf("number = %d\n", number);
}

void callByValue(int a) {
    a = a * a;
}

void callByPointer(int *a) {
    (*a) = (*a) * (*a);
}