求助为什么无法输出答案
```#include <stdio.h>
int main()
{
int n;
while(scanf("%d",&n)!=EOF)
{
int i;
char x[1000];
for(i=0;x[i]!='\n';i++)//输入序列x
{scanf("%c",&x[i]);}
if(x[i]>='a'&&x[i]<='z'||x[i]>='A'&&x[i]<='Z')
{
x[i]=x[i]+n;
if(x[i]>'z'||x[i]>'Z')
{
x[i]=x[i]-26;
}
}
printf("%c\n",x[i]);
}
return 0;
} ![图片说明](https://img-ask.csdn.net/upload/201912/08/1575792064_813405.png)