how do i get a pointer to "point" to a variable in another function?

this is what i have so far.

Code:# include <conio.h> # include <stdio.h> void calculations(int,int); void main (int sum,int diff) { int num1,num2; int * pointer1; int * pointer2; printf ("Enter num1: "); scanf("%d",&num1); printf ("Enter num2: "); scanf("%d",&num2); calculations(num1,num2); pointer1 =∑ pointer2 =&diff; printf ("The sum is : %d\n",pointer1); printf ("The sum is : %d\n",pointer2); getch(); } void calculations (int num1,int num2) { int sum,diff; sum = num1 + num2; diff = num1 - num2; }