如果有下面的代码
int select;
printf("1 for xxxx");
printf("2 for xxxx");
printf("3 for xxxx");
printf("please input you select:");
scanf("%d",&select);
如果用户输入的是1,2,3以外的字符或数字,就要重新输入,那么下面的代码应该怎么写?
#include <stdio.h>
int main()
{
int select;
printf("1 for xxxx\n");
printf("2 for xxxx\n");
printf("3 for xxxx\n");
printf("please input you select:\n");
scanf("%d",&select);
loop:
switch(select){
case 1 : printf("1 for xxxx\n"); break;
case 2 : printf("2 for xxxx\n"); break;
case 3 : printf("3 for xxxx\n"); break;
default : printf("please input you select again\n");
scanf("%d",&select);
goto loop;
}
return 0;
}
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第1个回答 2009-06-06
这里select的类型应该改成char，否则输入字符时将进入死循环。
char select;
printf("1 for xxxx");
printf("2 for xxxx");
printf("3 for xxxx");
printf("please input you select:");
do
scanf("%c",&select);
while (select < '1' || select > '3');
switch (select)
{
case '1':
break;
case '2':
break;
case '3':
break;
default:
break;
}本回答被提问者采纳
char select;
printf("1 for xxxx");
printf("2 for xxxx");
printf("3 for xxxx");
printf("please input you select:");
do
scanf("%c",&select);
while (select < '1' || select > '3');
switch (select)
{
case '1':
break;
case '2':
break;
case '3':
break;
default:
break;
}本回答被提问者采纳
第2个回答 2009-06-06
while(select>3||select<1){
scanf("%d",&select);
}
scanf("%d",&select);
}
