C++编写程序实现 二进制 八进制 十进制 十六进制相互转换 格式如下 一级菜单： （1）2进制数转换 （2）8进制数转换 （3）10进制数转换 （4）16进制数转换 （0）退出 二级菜单：（只是以2进制转其他进制为例，其他进制相同） （1）2进制数 ---> 8进制数 （2）2进制数 ---> 10进制数 （3）2进制数 ---> 16进制数 （0）返回上级目录

好的，以下是程序的代码：

#include <iostream>
#include <string>
#include <cmath>
using namespace std;

// 将二进制字符串转为十进制数
int binToDec(string bin)
{
    int dec = 0;
    for (int i = 0; i < bin.length(); i++) {
        dec += (bin[i] - '0') * pow(2, bin.length() - i - 1);
    }
    return dec;
}

// 将十进制数转为二进制字符串
string decToBin(int dec)
{
    string bin = "";
    while (dec != 0) {
        bin = to_string(dec % 2) + bin;
        dec /= 2;
    }
    return bin;
}

// 将二进制字符串转为八进制字符串
string binToOct(string bin)
{
    string oct = "";
    int len = bin.length();
    // 补全到3的倍数
    while (len % 3 != 0) {
        bin = "0" + bin;
        len = bin.length();
    }
    // 每三位二进制转为一位八进制
    for (int i = 0; i < len; i += 3) {
        string sub = bin.substr(i, 3);
        int dec = binToDec(sub);
        oct += to_string(dec);
    }
    return oct;
}

// 将八进制字符串转为二进制字符串
string octToBin(string oct)
{
    string bin = "";
    int len = oct.length();
    // 每一位八进制转为3位二进制
    for (int i = 0; i < len; i++) {
        int dec = oct[i] - '0';
        string sub = decToBin(dec);
        // 不足3位补全
        while (sub.length() < 3) {
            sub = "0" + sub;
        }
        bin += sub;
    }
    // 去掉前导0
    int pos = bin.find_first_not_of('0');
    if (pos != string::npos) {
        bin = bin.substr(pos);
    } else {
        bin = "0";
    }
    return bin;
}

// 将二进制字符串转为十六进制字符串
string binToHex(string bin)
{
    string hex = "";
    int len = bin.length();
    // 补全到4的倍数
    while (len % 4 != 0) {
        bin = "0" + bin;
        len = bin.length();
    }
    // 每四位二进制转为一位十六进制
    for (int i = 0; i < len; i += 4) {
        string sub = bin.substr(i, 4);
        int dec = binToDec(sub);
        if (dec < 10) {
            hex += to_string(dec);
        } else {
            hex += (char)('A' + dec - 10);
        }
    }
    return hex;
}

// 将十六进制字符串转为二进制字符串
string hexToBin(string hex)
{
    string bin = "";
    int len = hex.length();
    // 每一位十六进制转为4位二进制
    for (int i = 0; i < len; i++) {
        int dec = 0;
        if (hex[i] >= '0' && hex[i] <= '9') {
            dec = hex[i] - '0';
        } else if (hex[i] >= 'A' && hex[i] <= 'F') {
            dec = hex[i] - 'A' + 10;
        }
        string sub = decToBin(dec);
        // 不足4位补全
        while (sub.length() < 4) {
            sub = "0" + sub;
        }
        bin += sub;
    }
    // 去掉前导0
    int pos = bin.find_first_not_of('0');
    if (pos != string::npos) {
        bin = bin.substr(pos);
    } else {
        bin = "0";
    }
    return bin;
}

int main()
{
    int choice1, choice2;
    string num;
    cout << "一级菜单：" << endl;
    cout << "（1）2进制数转换" << endl;
    cout << "（2）8进制数转换" << endl;
    cout << "（3）10进制数转换" << endl;
    cout << "（4）16进制数转换" << endl;
    cout << "（0）退出" << endl;
    cout << "请输入您的选择：";
    cin >> choice1;
    while (choice1 != 0) {
        switch (choice1) {
            case 1:
                cout << "二级菜单：" << endl;
                cout << "（1）2进制数  --->  8进制数" << endl;
                cout << "（2）2进制数  --->  10进制数" << endl;
                cout << "（3）2进制数  --->  16进制数" << endl;
                cout << "（0）返回上级目录" << endl;
                cout << "请输入您的选择：";
                cin >> choice2;
                while (choice2 != 0) {
                    cout << "请输入一个二进制数：";
                    cin >> num;
                    switch (choice2) {
                        case 1:
                            cout << "转换结果为：" << binToOct(num) << endl;
                            break;
                        case 2:
                            cout << "转换结果为：" << binToDec(num) << endl;
                            break;
                        case 3:
                            cout << "转换结果为：" << binToHex(num) << endl;
                            break;
                        default:
                            cout << "输入错误，请重新输入！" << endl;
                            break;
                    }
                    cout << "请输入您的选择：";
                    cin >> choice2;
                }
                break;
            case 2:
                cout << "二级菜单：" << endl;
                cout << "（1）8进制数  --->  2进制数" << endl;
                cout << "（2）8进制数  --->  10进制数" << endl;
                cout << "（3）8进制数  --->  16进制数" << endl;
                cout << "（0）返回上级目录" << endl;
                cout << "请输入您的选择：";
                cin >> choice2;
                while (choice2 != 0) {
                    cout << "请输入一个八进制数：";
                    cin >> num;
                    switch (choice2) {
                        case 1:
                            cout << "转换结果为：" << octToBin(num) << endl;
                            break;
                        case 2:
                            cout << "转换结果为：" << stoi(num, nullptr, 8) << endl;
                            break;
                        case 3:
                            cout << "转换结果为：" << binToHex(octToBin(num)) << endl;
                            break;
                        default:
                            cout << "输入错误，请重新输入！" << endl;
                            break;
                    }
                    cout << "请输入您的选择：";
                    cin >> choice2;
                }
                break;
            case 3:
                cout << "二级菜单：" << endl;
                cout << "（1）10进制数  --->  2进制数" << endl;
                cout << "（2）10进制数  --->  8进制数" << endl;
                cout << "（3）10进制数  --->  16进制数" << endl;
                cout << "（0）返回上级目录" << endl;
                cout << "请输入您的选择：";
                cin >> choice2;
                while (choice2 != 0) {
                    cout << "请输入一个十进制数：";
                    cin >> num;
                    switch (choice2) {
                        case 1:
                            cout << "转换结果为：" << decToBin(stoi(num)) << endl;
                            break;
                        case 2:
                            cout << "转换结果为：" << oct(stoi(num)) << endl;
                            break;
                        case 3:
                            cout << "转换结果为：" << hex << stoi(num) << endl;
                            break;
                        default:
                            cout << "输入错误，请重新输入！" << endl;
                            break;
                    }
                    cout << "请输入您的选择：";
                    cin >> choice2;
                }
                break;
            case 4:
                cout << "二级菜单：" << endl;
                cout << "（1）16进制数  --->  2进制数" << endl;
                cout << "（2）16进制数  --->  8进制数" << endl;
                cout << "（3）16进制数  --->  10进制数" << endl;
                cout << "（0）返回上级目录" << endl;
                cout << "请输入您的选择：";
                cin >> choice2;
                while (choice2 != 0) {
                    cout << "请输入一个十六进制数：";
                    cin >> num;
                    switch (choice2) {
                        case 1:
                            cout << "转换结果为：" << hexToBin(num) << endl;
                            break;
                        case 2:
                            cout << "转换结果为：" << binToOct(hexToBin(num)) << endl;
                            break;
                        case 3:
                            cout << "转换结果为：" << stoi(num, nullptr, 16) << endl;
                            break;
                        default:
                            cout << "输入错误，请重新输入！" << endl;
                            break;
                    }
                    cout << "请输入您的选择：";
                    cin >> choice2;
                }
                break;
            default:
                cout << "输入错误，请重新输入！" << endl;
                break;
        }
        cout << "一级菜单：" << endl;
        cout << "（1）2进制数转换" << endl;
        cout << "（2）8进制数转换" << endl;
        cout << "（3）10进制数转换" << endl;
        cout << "（4）16进制数转换" << endl;
        cout << "（0）退出" << endl;
        cout << "请输入您的选择：";
        cin >> choice1;
    }
    return 0;
}

这个程序可以实现二进制、八进制、十进制、十六进制之间的相互转换。在输入选择后，会进入对应的二级菜单，再根据提示输入转换的数值即可得到转换结果。