题解 | #字符串加解密#

#include <cctype>
#include <iostream>
#include <string>
using namespace std;
string jiami(string& str) 
{
    for (int i = 0; i < str.size(); i++) {
        if (str[i] >= 'a' && str[i] <= 'z') {
            if (str[i] == 'z')
                str[i] = 'A';
            else
                str[i] = toupper(str[i]) + 1;
        } else if (str[i] >= 'A' && str[i] <= 'Z') {
            if (str[i] == 'Z')
                str[i] = 'a';
            else
                str[i] = tolower(str[i]) + 1;
        } else if (isdigit(str[i])) {
            if (str[i] == '9')
                str[i] = '0';
            else
                str[i] += 1;
        }
    }
    return str;
}
string jiemi(string& str) 
{
    for (int i = 0; i < str.size(); i++) {
        if (str[i] >= 'a' && str[i] <= 'z') {
            if (str[i] == 'a')
                str[i] = 'Z';
            else
                str[i] = toupper(str[i]) - 1;
        } else if (str[i] >= 'A' && str[i] <= 'Z') {
            if (str[i] == 'A')
                str[i] = 'z';
            else
                str[i] = tolower(str[i]) - 1;
        } else if (isdigit(str[i])) {
            if (str[i] == '0')
                str[i] = '9';
            else
                str[i] -= 1;
        }
    }
    return str;

}
int main() {
    string str1;//加密数据
    string str2;//解密数据
    while (cin>>str1>>str2) 
    {
        string ans=jiami(str1);
        cout << ans << endl;
        ans=jiemi(str2);
        cout << ans << endl;
    }
    return 0;

}