这里是代码

#include<iostream>
#include<stdio.h>
using namespace std;
int main()
{
    int n,l=0;
    cin >> n;
    string str1;
    cin >> str1;
    l = size(str1);
    for (int i = 0; i<=l-1;i++)
    {
        str1[i] += n;
        if (str1[i] > 'z')
        {
            int t = (int)str1[i]-122;
            str1[i] = (t % 26) + 'a'-1;
        }
    }
    cout << str1;
    return 0;
}