switch( ) case 1: default: break;
switch(a)
{
case 1:
case 2:
printf("你输入了1或2\n");
break;
default:
printf("输入错误\n");
break;
}

switch( ) case 1: default: break;
switch(a)
{
case 1:
case 2:
printf("你输入了1或2\n");
break;
default:
printf("输入错误\n");
break;
}