組み込みシステム開発における C++ データ変換およびエンコードおよびデコード機能の実装スキル

#include <iostream>
#include <sstream>

int main() {
    int num = 123;
    std::ostringstream oss;
    oss << num;
    std::string str = oss.str();
    std::cout << "Integer to string: " << str << std::endl;
    
    return 0;
}

#include <iostream>
#include <string>
#include <sstream>

int main() {
    std::string str = "123";
    std::istringstream iss(str);
    int num;
    iss >> num;
    std::cout << "String to integer: " << num << std::endl;

    return 0;
}

#include <iostream>

int main() {
    double num = 3.14;
    int integer = static_cast<int>(num);
    std::cout << "Double to integer: " << integer << std::endl;

    return 0;
}

#include <iostream>

int main() {
    int integer = 3;
    double num = static_cast<double>(integer);
    std::cout << "Integer to double: " << num << std::endl;

    return 0;
}

#include <iostream>
#include <string>
#include <cstring>
#include <zlib.h>

std::string compress(const std::string& str) {
    z_stream zs;
    memset(&zs, 0, sizeof(zs));
    
    if (deflateInit(&zs, Z_DEFAULT_COMPRESSION) != Z_OK) {
        return "";
    }
    
    zs.next_in = (Bytef*)(str.c_str());
    zs.avail_in = str.size() + 1;
    
    char outbuffer[32768];
    std::string outstring;
    
    do {
        zs.next_out = reinterpret_cast<Bytef*>(outbuffer);
        zs.avail_out = sizeof(outbuffer);
        
        if (deflate(&zs, Z_FINISH) == Z_STREAM_ERROR) {
            deflateEnd(&zs);
            return "";
        }
        
        outstring.append(outbuffer, sizeof(outbuffer) - zs.avail_out);
        
    } while (zs.avail_out == 0);
    
    deflateEnd(&zs);
    
    return outstring;
}

std::string decompress(const std::string& str) {
    z_stream zs;
    memset(&zs, 0, sizeof(zs));
    
    if (inflateInit(&zs) != Z_OK) {
        return "";
    }
    
    zs.next_in = (Bytef*)(str.c_str());
    zs.avail_in = str.size();
    
    char outbuffer[32768];
    std::string outstring;
    
    do {
        zs.next_out = reinterpret_cast<Bytef*>(outbuffer);
        zs.avail_out = sizeof(outbuffer);
        
        if (inflate(&zs, 0) == Z_STREAM_ERROR) {
            inflateEnd(&zs);
            return "";
        }
        
        outstring.append(outbuffer, sizeof(outbuffer) - zs.avail_out);
        
    } while (zs.avail_out == 0);
    
    inflateEnd(&zs);
    
    return outstring;
}

int main() {
    std::string str = "Hello, World!";
    
    // 压缩
    std::string compressed = compress(str);
    std::cout << "Compressed: " << compressed << std::endl;
    
    // 解压缩
    std::string decompressed = decompress(compressed);
    std::cout << "Decompressed: " << decompressed << std::endl;
    
    return 0;
}

#include <iostream>
#include <string>
#include <openssl/aes.h>
#include <openssl/rand.h>

std::string encrypt(const std::string& key, const std::string& plain) {
    std::string encrypted;
    AES_KEY aesKey;
    
    if (AES_set_encrypt_key(reinterpret_cast<const unsigned char*>(key.c_str()), 128, &aesKey) < 0) {
        return "";
    }
    
    int len = plain.length();
    
    if (len % 16 != 0) {
        len = (len / 16 + 1) * 16;
    }
    
    unsigned char outbuffer[1024];
    memset(outbuffer, 0, sizeof(outbuffer));
    AES_encrypt(reinterpret_cast<const unsigned char*>(plain.c_str()), outbuffer, &aesKey);
    
    encrypted.assign(reinterpret_cast<char*>(outbuffer), len);
    
    return encrypted;
}

std::string decrypt(const std::string& key, const std::string& encrypted) {
    std::string decrypted;
    AES_KEY aesKey;
    
    if (AES_set_decrypt_key(reinterpret_cast<const unsigned char*>(key.c_str()), 128, &aesKey) < 0) {
        return "";
    }
    
    unsigned char outbuffer[1024];
    memset(outbuffer, 0, sizeof(outbuffer));
    AES_decrypt(reinterpret_cast<const unsigned char*>(encrypted.c_str()), outbuffer, &aesKey);
    
    decrypted.assign(reinterpret_cast<char*>(outbuffer));
    
    return decrypted;
}

int main() {
    std::string key = "1234567890123456";
    std::string plain = "Hello, World!";
    
    // 加密
    std::string encrypted = encrypt(key, plain);
    std::cout << "Encrypted: " << encrypted << std::endl;
    
    // 解密
    std::string decrypted = decrypt(key, encrypted);
    std::cout << "Decrypted: " << decrypted << std::endl;
    
    return 0;
}