程序代码：

#include <stdio.h>
#include <string.h>

int main()
{
    char *an[5]={"优","良","中","及格","不及格"};
    char *ad[5]={"90-100","80-89","70-79","60-69","0-59"};
    int i;
    char n[10];
    scanf("%s",n);
    for (i=0;i<5;++i)
    {
        if (strcmp(n,an[i])==0)
        {
            printf("%s %s\n", an[i],ad[i]);
            break;
        }
    }
    return 0;
}

程序代码：

#include <stdio.h>
#include <string.h>

int main(void)
{
    char *f;
    char val[10] = {0};
    while (1) // Ctrl+C退出
    {
        printf("五分制成绩(优/良/中/及格/不及格)：\n");
        if (fgets(val, 10, stdin))
        {
            if (f = strchr(val, '\n'))
                *f = '\0';
            else
                while (getchar() != '\n') //清空缓冲区
                    ;
            if (!strcmp(val, "优"))
                printf("成绩：90-100\n");
            else if (!strcmp(val, "良"))
                printf("成绩：80-89\n");
            else if (!strcmp(val, "中"))
                printf("成绩：70-79\n");
            else if (!strcmp(val, "及格"))
                printf("成绩：60-69\n");
            else if (!strcmp(val, "不及格"))
                printf("成绩：0-59\n");
            else
                printf("输入有误，重新输入\n");
        }
        else
        {
            printf("输入读取失败\n");
            break;
        }
    }
    return 0;
}