求问为啥第四点过不去！！！

bjrjk @ 2016-01-26 19:59:59

#include <iostream>
#include <string>
using namespace std;
int main(){
    int a;
    string str;
    cin>>a;
    a%=26;
    cin>>str;
    for(int i=0;i<str.length();i++){
        str[i]=int(str[i]+a);
    }
    cout<<str;
    return 0;
}

by 寻梦 @ 2016-06-25 09:22:38

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
int main()
{
    char a[100];
    int n,x,k;
    cin>>n;
    cin>>a;
    x=strlen(a)-1;
    for (int i=0;i<=x;i++)
     {
         k=a[i]+n;
         if (k>122) k-=26;
         a[i]=k;
     }
    for (int i=0;i<=x;i++)
     cout<<a[i];
  return 0;
}