#include<stdio.h>
void main()
{
    char c;
    int k;
    printf("Input k:");
    scanf("%d",&k);
    getchar();
    c=getchar();
    while(c!='\n'){
        if((c>='a'&&c<='z')||(c>='A'&&c<='Z'))
        {   c=c+k;
            if(c>'z'||c>'Z'&&c<='Z'+k)
                c=c-26;
        }
        printf("%c",c);
        c=getchar();
    }
}
  教科书结果：
Input k: 5
Asdf234GT#
Fxik234LY#
求助！！！！