题解 | #字符串加解密#

#include <iostream>
using namespace std;
int en(char c) {
    int x = c;
    if (c >= 'a' && c <= 'z') x = (c - 'a' + 1) % 26 + 'A';
    if (c >= 'A' && c <= 'Z') x = (c - 'A' + 1) % 26 + 'a';
    if (c >= '0' && c <= '9') x = (c - '0' + 1) % 10 + '0';
    return x;
}
int de(char c) {
    int x = c;
    if (c >= 'a' && c <= 'z') x = (c - 'a' + 25) % 26 + 'A';
    if (c >= 'A' && c <= 'Z') x = (c - 'A' + 25) % 26 + 'a';
    if (c >= '0' && c <= '9') x = (c - '0' + 9) % 10 + '0';
    return x;
}
int main() {
    string s,s1;
    int i, len;
    char c;
    cin >> s;
    len = s.length();
    for (i = 0; i < len; i++) {
        c = en(s[i]);
        cout << c;
    }
    cout << endl;
    cin >> s1;
    len = s1.length();
    for (i = 0; i < len; i++) {
        c = de(s1[i]);
        cout << c;
    }
    cout << endl;
}
// 64 位输出请用 printf("%lld")

大半夜的。。。以为英文字母是24个