int grade(int a,int b,int c, bool sum)
{
return (sum ? (a + b + c) : ((a + b + c) /3));
}

#include <stdoi.h>
#include <stdlib.h>
void grade(int,int,int);

int main(void)
{
    int a,b,c;
    printf("请输入三科成绩:\n");
    scanf("%d %d %d",&a,&b,&c);
    printf("sum=%d avg=%d\n",grade(j),grade(avg));
    system("pause");
    return 0;
    }
void grade(int a,int b,int c,int &avg));
{
    int j = a + b + c;
   avg = j / 3;
return j;
    
    }