al4_5.c

里面告诉了许多你编程用的方法和例子

/*案例代码文件名：AL4_5.C。*/
main()
{ int  score, grade;
  printf("Input a score(0~100): ");
  scanf("%d", &score);
  grade = score/10;					/*将成绩整除10，转化成switch语句中的case标号*/
  switch (grade)
  { case  10:
    case    9: printf("grade=A\n"); break;		/*标号10和9，都执行本行的2条语句*/
    case    8: printf("grade=B\n"); break;
    case    7: printf("grade=C\n"); break;
    case    6: printf("grade=D\n"); break;
    case    5:
    case    4:
    case    3:
    case    2:
    case    1:
    case    0: printf("grade=E\n"); break;		/*标号5、4、3、2、1和0，都执行本行的2条语句
*/
    default: printf("The score is out of range!\n");	/*成绩超出范围时，提示出错*/
  }
}