>>307
a)
#include <stdio.h>
double average(int a, int b, int c){return (double)(a+b+c)/3;}
int main(){
int a,b,c;
printf("a=");scanf("%d", &a);
printf("b=");scanf("%d", &b);
printf("c=");scanf("%d", &c);
printf("average=%f", average(a, b, c));
}