帮我优化这段代码#include <iostream> #include<iomanip> #include<string> using namespace std; int main() { cout<<"2022116487 叶新于\n"; string message; cout << "请输入要加密的信息："; getline(cin, message); const string alphabet = "abcdefghijklmnopqrstuvwxyz"; string encrypted_message = ""; for (char c : message) { if (isalpha(c)) { size_t index = alphabet.find(tolower(c)); char new_c = alphabet[(index + alphabet.size() - 5) % alphabet.size()]; encrypted_message += isupper(c) ? toupper(new_c) : new_c; } else { encrypted_message += c; } } cout << "加密后的信息为：" << encrypted_message << endl; system ("pause"); return 0; }

这段代码已经非常简洁了，但还是可以进行一些优化：

1. 可以将输入密码的部分改为使用 cin，避免输入空格时出错：

cout << "请输入要加密的信息：";
cin >> ws; // 忽略输入流中的空白字符
getline(cin, message);

2. 可以将常量字符串 alphabet 定义为全局变量，避免在循环中重复定义：

const string alphabet = "abcdefghijklmnopqrstuvwxyz";

3. 可以将加密代码封装成一个函数，提高代码复用性：

string encrypt(string message, int shift) {
    const string alphabet = "abcdefghijklmnopqrstuvwxyz";
    string encrypted_message = "";
    for (char c : message) {
        if (isalpha(c)) {
            size_t index = alphabet.find(tolower(c));
            char new_c = alphabet[(index + shift + alphabet.size()) % alphabet.size()];
            encrypted_message += isupper(c) ? toupper(new_c) : new_c;
        } else {
            encrypted_message += c;
        }
    }
    return encrypted_message;
}

完整代码如下：

#include <iostream>
#include <string>

using namespace std;

const string alphabet = "abcdefghijklmnopqrstuvwxyz";

string encrypt(string message, int shift) {
    string encrypted_message = "";
    for (char c : message) {
        if (isalpha(c)) {
            size_t index = alphabet.find(tolower(c));
            char new_c = alphabet[(index + shift + alphabet.size()) % alphabet.size()];
            encrypted_message += isupper(c) ? toupper(new_c) : new_c;
        } else {
            encrypted_message += c;
        }
    }
    return encrypted_message;
}

int main() {
    cout << "2022116487 叶新于\n";
    string message;
    cout << "请输入要加密的信息：";
    cin >> ws;
    getline(cin, message);
    cout << "加密后的信息为：" << encrypt(message, -5) << endl;
    system("pause");
    return 0;
}