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