例4.7

# include<stdio.h>
int main()
{
 void action1(int,int),action2(int,int);
char ch;
  int a=15,b=23;
  ch=getchar();
  switch(ch)
  {
case'a':
case'A':action1(a,b);break;
case'b':
case'B':action2(a,b);break;
default:putchar('\a');
}
return 0;
}