#include<iostream>
using namespace std;
void main(){
cout<<"请输入成绩";
int score;
cin>>score;
while(score<0||score>100){
cout<<"您输入的成绩不符合要求，请重新输入";
cin>>score;
}
switch(score/10){
case 10:
case 9:
cout<<"A";
break;
case 8:
cout<<"B";
break;
case 7:
cout<<"C";
break;
case 6:
cout<<"D";
break;
default:
cout<<"E";
}
system("pause");
}
这种情况是标准的使用switch的情况，用if也行，更简单：
#include<iostream>
using namespace std;
void main(){
cout<<"请输入成绩";
int score;
cin>>score;
while(score<0||score>100){
cout<<"您输入的成绩不符合要求，请重新输入";
cin>>score;
}
if(score>=90){
cout<<"A";
}else{
if(score>=80){
cout<<"B";
}else{
if(score>=70){
cout<<"C";
}else{
if(score>=60){
cout<<"D";
}else{
cout<<"E";
}
}
}
}
system("pause");
}
#include <stdio.h>
main()
{ float score;
char grade;
printf("请输入学生成绩：");
scanf("%f",&score);
while(score>100||(score<0)
{ printf("\n输入有误,请重新输入：");
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%5.1f，相应的等级是%c。\n",score,grade);
说明：对输入的数据进行检查，如小于0或大于100，要求重新输入。(int)(score/10)的作用是将 (score/10) 的值进行强制类型转换，得到一个整型值。