题解 | #字符串加解密#

#include <iostream>
using namespace std;

void encode(string& s) {
    for (int i = 0; i < s.size(); i++) {
        if (isdigit(s[i])) {
            if (s[i] != '9')s[i] += 1;
            else s[i] = '0';
        } 
        else if ('a' <= s[i] && s[i] <= 'z') {//原码小写
            if (s[i] != 'z') s[i] = toupper(s[i]) + 1;
            else s[i] = 'A';
        } 
        else {
            if (s[i] != 'Z') s[i] = tolower(s[i]) + 1;
            else s[i] = 'a';
        }
    }
}
void decode(string& s) {
    for (int i = 0; i < s.size(); i++) {
        if (isdigit(s[i])) {
            if (s[i] != '0')s[i] -= 1;
            else s[i] = '9';
        } 
        else if ('a' <= s[i] && s[i] <= 'z') {
            if (s[i] != 'a') s[i] = toupper(s[i]) - 1;
            else s[i] = 'Z';
        } 
        else {
            if (s[i] != 'A') s[i] = tolower(s[i]) - 1;
            else s[i] = 'z';
        }
    }
}
int main() {
    string s1, s2;
    cin >> s1;
    cin >> s2;
    encode(s1);
    decode(s2);
    cout << s1 << endl;
    cout << s2 << endl;
    return 0;
}
// 64 位输出请用 printf("%lld")