编辑代码

#include <stdio.h>
int main ()
{float score;
char grade;
printf ("请输入学生成绩:\n");
scanf ("%f",&score);
while (score<0||score>100) 
{printf ("输入有误，请重新输入:\n");  //没有分块，while将一直循环该语句。
scanf ("%f",&score);}
switch ((int)(score/10))
{case 10:
case 9: grade='A';break;
case 8: grade='B';break;
case 7: grade='C';break;
case 6: grade='D';break;
case 5:
case 4:
case 3:
case 2:
case 1:
case 0: grade='E';}
printf ("成绩是：%.1f\n等级是：%c",score,grade);
return 0;
}