编写三个函数分别求某学生三门课程总成绩和平均成绩和及格率

#include <stdio.h>
int main()
{
float sum(float b[3]);
float passr(float b[3]);
float aver(float b[3]);

int i;
float b[3];
for (i=0;i<3;i++)
scanf ("%f",&b[i]);
printf("sum=%5.2f\npassr=%5.2f\naver=%5.2f\n",sum(b),passr(b),aver(b));
return 0;
}

float passr(float b[]){
int i,k=0;
for (i=0;i<3;i++){
if (b[i]>=60)
k++;
}
return (k/3.0);
}

float sum(float b[]){
float sum=0.0;
int i;
for (i=0;i<3;i++)
sum+=b[i];
return (sum);
}

float aver(float b[]){
float a;
a=sum(b);
return (a/3);
}