分支结构 + 字符串更改

#include<bits/stdc++.h>
using namespace std;
int main(){
    char k[60];gets(k);
    for(int i=0;i<strlen(k);i++){
        if(k[i]>='a' and k[i]<'x') cout<<char(k[i]+1)<<char(k[i]+2)<<char(k[i]+3);
        else if(k[i]=='x') cout<<"yza";
        else if(k[i]=='y') cout<<"zab";
        else if(k[i]=='z') cout<<"abc";
        else cout<<k[i];
    }
    return 0;
}