求两个数相加的c语言程序

就是两个数相加
用函数~~谢谢~

public int sum(int a, int b) {
int count = 0;
count = a + b;
return count;
}

#include <stdio.h>

int sum(int a, int b);

int main(void)
{
int a = 123, b = 456;

printf("a + b = %d", sum(a, b));
}

int sum(int a, int b)
{
return a + b;
}