Wrong Answer
代码
#include <stdio.h>
#include <ctype.h>
#define N 5
#define KEY 4
int
main(void)
{
    char str[N+1];
    for (int i=0; i < N; i++)
        str[i] = getchar();
    for (int i=0; i < N; i++)
    {   
        if (islower(str[i]))
            str[i] = (str[i] + KEY - 'a' ) % 26 + 'a';
        else if (isupper(str[i]))
            str[i] = (str[i] + KEY - 'A' ) % 26 + 'A';
    }
    for (char *p=str; *p != '\0'; p++)
        printf("%c", *p);
    return 0;
}