#include <stdio.h>
#include <stdlib.h>

int main()
{
    int grade=-1;
    char gradeLevel='A';
    char getGradeLevel(int grade);
    while(1)
    {
         printf("请输入成绩：");
        scanf("%d",&grade);
        gradeLevel=getGradeLevel(grade);
        printf("成绩%d的等级是%c\n",grade,gradeLevel);
        if(grade!=0)
            continue;
            else
                break;
    }
    return 0;
}
#include<stdio.h>
#include<stdlib.h>
char getGradeLevel(int grade)
{
    int score;
    switch(score)
    {
    case 0:
    case 1:
    case 2:
    case 3:
    case 4:
    case 5:
        printf("E");
    case 6:
        printf("D");
    case 7:
        printf("C");
    case 8:
        printf("B");
    case 9:
    case 10:
        printf("A");
    }
    if(grade<0||grade>100)
        return (score);
}
各位大神帮忙看看是哪里出问题了，谢谢

忘记写了

好像这样就可以了，不过编译生成那里还有个varning