Can't use a char variable in my equation

#include <stdio.h>

main()
{
	char mod;
	int x, y, z;

	x = 5;
	y = 6;

	

	printf("Enter in an operator ---> ");
	scanf("%c", &mod);
	
	
	z = ((x) mod (y));  /* want this equation to 
work, I want x to be added, subtrated, whatever 'mod' i
s to y and save it in z */

	printf("\n");
	printf("%d\n", z);
	

	printf("\n");
	printf("%c\n", mod);
	return 0;
}

switch (op) {
   case '+':
      return a + b;
   case '*':
      return a * b;

   /* and so on... */

   default:
      /* not a valid operator */
}