例4-2 求平均分

例4-2 求平均分

更改例3-3，计算平均分、统计不合格人数
程序核心——if语句

程序

#include<stdio.h>
int main()
{
    int count,num;
    double grade,total;
    
    num=total=count;
    printf("Enter grades:"); 
    scanf("%lf",&grade);
    
    while(grade>=0)
    {
        total+=grade;
        num++;
        if(grade<60)
            count++;
        scanf("%lf",&grade);
    } 
    if(num!=0)
    {
        printf("Grade average is %.2f",total/num);
        printf("Number of failures is %d",count);
    } 
    else
        printf("Grade averageis 0");
    
} 

结果

Enter grades:58 78 87 90 -1
Grade average is 78.25Number of failures is 1
--------------------------------
Process exited after 36.19 seconds with return value 0
请按任意键继续. . .

分析

重点：while语句