Question

C语言的小问题，帮忙解答一下，thanks very much!

#include<stdio.h>
main()
{
long x;
int a,b,c,d,e,f;
b=(int)(x/10000);
c=(int)((x-b*10000)/1000);
d=(int)((x-b*10000-c*1000)/100);
e=(int)((x-b*10000-c*1000-d*100)/10);
f=(int)(x-b*10000-c*1000-d*100-e*10);
scanf("%ld",&x);
while(x<=0||x>=100000)
{
printf("输入错误，请重新输入：\n");
scanf("%ld",&x);
}
if(x<10) a=1;
else if(x<100) a=2;
else if(x<1000) a=3;
else if(x<10000) a=4;
else (x<100000) a=5;
printf("%d\n",a);
switch(a)
{
case 1:printf("%ld\n",f);
printf("%ld\n",f);break;
case 2:printf("%ld%ld\n",e,f);
printf("%ld%ld\n",f,e);break;
case 3:printf("%ld%ld%ld\n",d,e,f);
printf("%ld%ld%ld\n",f,e,d);break;
case 4:printf("%ld%ld%ld%ld\n",c,d,e,f);
printf("%ld%ld%ld%ld\n",f,e,d,c);break;
case 5:printf("%ld%ld%ld%ld%ld\n",b,c,d,e,f);
printf("%ld%ld%ld%ld%ld\n",f,e,d,c,b);break;
}
printf("over.\n");
}
问题是：给一个不多于5位的正整数，求1：它是几位数；2：分别输出每一位数字；3：按逆序输出各位数字．
我编为什么会出现一个错误．

Answer 1

语法错误：

else (x<100000) a=5;
改为
else if (x<100000) a=5;

算法错误：

b=(int)(x/10000);
c=(int)((x-b*10000)/1000);
d=(int)((x-b*10000-c*1000)/100);
e=(int)((x-b*10000-c*1000-d*100)/10);
f=(int)(x-b*10000-c*1000-d*100-e*10);
scanf("%ld",&x);

应改为

scanf("%ld",&x);
b=(int)(x/10000);
c=(int)((x-b*10000)/1000);
d=(int)((x-b*10000-c*1000)/100);
e=(int)((x-b*10000-c*1000-d*100)/10);
f=(int)(x-b*10000-c*1000-d*100-e*10);

Answer 2

在main 函数中在定义完long x;后用scanf("%ld",&x); 进行复值,就可以了.
你的程序里面其实跟你输入的X无关,它是系统给的一个随即数,你单步执行下就可以看见.