我都快不想发题解了

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
int main(){
    char a[1000];
    gets(a);
    int len = strlen(a);
    int n = 1;
    for(int i = 0; i < len; i++){
        if(a[i] >= 'A' and a[i] <= 'Z' - n){
            a[i] += n;
        }else if(a[i] >= 'a' and a[i] <= 'z' - n){
            a[i] += n;
        }else if(a[i] > 'Z' - n and a[i] <= 'Z'){
            a[i] = a[i] - (26 - n);
        }else if(a[i] > 'z' - n and a[i] <= 'z'){
            a[i] = a[i] - (26 - n);
        }
    }
    cout << a;
    return 0;
}