程序代码：

#include<stdio.h>              
main()                         
{                              

 int score;                    

 printf("成绩：");             

 scanf("%d",&score);           

 switch(score/10);             
{                              
  case10:                      
  case9:printf("优\n");break;  
  case8:printf("良\n");break;  
  case7:printf("中\n");break;  
  case6:printf("及格\n");break;
  case5:                       
  case4:                       
  case3:                       
  case2:                       
  case1:                       
  case0:printf("不及格\n");break;    
  default:printf("错误\n");
}                              
}