C :: Menu Driven Array Of Function Pointers Calculator

The premise of this assignment is to create a menu driven, array of functions calculator. This is the code I have thus far (I haven't finished all of my comments yet, I've been to focused on clearing errors).

Code:
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

/*prototypes*/
void sum (int a, int b);
void dif (int a, int b);
void pro (int a, int b);
void quo (int a, int b);
void printMenu();

[Code] .....

I am using Visual Studio as a compiler, and I have the following errors:

error C2144: syntax error : 'int' should be preceded by ')'
error C2660: 'sum' : function does not take 0 arguments
error C2059: syntax error : ')'
error C2144: syntax error : 'int' should be preceded by ')'

[Code] .....

I can only assume that I am making simple mistakes.