为什么一直0呢

一直"Too many or too few lines"

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int d;
char s[1000000];
int main()
{
    cin>>d;
    getchar();
    gets(s);
    d%=26;
    for(int i=0;i<strlen(s);i++)
    {
        s[i]+=d;
        if(s[i]>'z')
            s[i]=s[i]-'z'+'a';
        putchar(s[i]);
    }
    return 0;
}