// 24T3 COMP1511 Week 5 Lecture 2
// variables/data are passed into functions by value
// a copy of the value gets passed into the function
// Here we pass in the addresses of the variables
// so we can go directly to their address and modify
// them from within the function

#include <stdio.h>

void update(int *x, int *y);
// TO DO FIX SWAP
void swap(int *x, int *y);

int main(void) {
    int x = 2;
    int y = 5;

    printf("%d %d\n", x, y);
    
    // Pass in the addresses of x and y
    // So update can use the addresses to
    // go modify x and y 
    update(&x, &y);
    printf("%d %d\n", x, y);
    
    //TODO FIX THIS
    swap(&x, &y);
    printf("%d %d\n", x, y);
    return 0;
}

// This function uses pointers.
// We can dereference x and y and modify the data
// at the given addresses
void update(int *x, int *y) {
    *x = *x + 1;
    *y = *y - 1;
}

// This function will only modify the local copy of x and y
// TODO FIX
void swap(int *x, int *y) {
    int tmp = *x;
    *x = *y;
    *y = tmp;
}