如何在同一个 srand() 种子中获得两个不同的随机数？ C++

感谢@RetiredNinja 指出问题不在于 srand()，而在于我的数组中函数调用不当。使用 switch 语句正确调用函数解决了问题。

//improper calling of functions in an array. Resolved with switch statement below
//char randomCharacterTypes[4] = {randomLowerCharacter(),randomInt(),randomCapitalCharacter(),randomSpecialCharacter()};

while (numberOfCharacters > 0){
    int random = rand()%4;
    switch(random){
    case 0:
        @R_607_5747@d += randomLowerCharacter();
        break;
    case 1:
        @R_607_5747@d += randomInt();
        break;
    case 2:
        @R_607_5747@d += randomCapitalCharacter();
        break;
    case 3:
        @R_607_5747@d += randomSpecialCharacter();
        break;
    }
    numberOfCharacters--;
}

randomCharacterTypes 是一个包含 4 个字符的数组，对于每个字符类，您将始终获得相同的字符。如果您想每次都生成一个新字符，则可以改用函数指针：

String randomGenerator(int numberOfCharacters){
    char (*randomCharacterTypes[])() = {randomLowerCharacter,randomInt,randomCapitalCharacter,randomSpecialCharacter};
    std::string @R_607_5747@d;

    while (numberOfCharacters > 0){
        int random = rand()%4;
        @R_607_5747@d += randomCharacterTypes[random]();
        numberOfCharacters--;
    }
    return @R_607_5747@d;
}

randomInt 可以简化为返回 '0' 和 '9' 之间的字符，与您的其他函数相同：

char randomInt(){
    return '0' + rand() % 10;
}

如果您使用字符而不是数字，那么您的其他函数将更具可读性，然后您必须添加注释以提醒您它们代表哪个字符：

char randomLowerCharacter(){
    return 'a' + rand()%26;
}
char randomCapitalCharacter(){
    return 'A' + rand()%26;
}
char randomSpecialCharacter(){
    /** Special characters are split by numbers so we pick a random from one of the 2 groups.*/
    return (rand()%2) ? char('!' + rand()%14) : char(':' + rand()%8); 
}

请注意，rand() % x 不是一个好的随机数生成器，您应该改用标准库随机函数（尤其是当您将这些密码用于任何重要的事情时）。

可以使用 String 来进一步简化您的代码以包含您的字符类：

#include <String>
#include <String_view>
#include <iostream>
#include <random>
#include <array>

class @R_607_5747@dGenerator
{
public:
    @R_607_5747@dGenerator()
    {
        for (size_t i = 0; i < characterTypes.size(); i++)
        {
            characterTypeDiStributions[i] = std::uniform_int_diStribution<int>(0,characterTypes[i].size() - 1);
        }
    }

    static constexpr std::array<std::string_view,4> characterTypes = {
            "abcdefghijklmnopqrstuvwxyz","ABCDEFGHIJKLMNOPQRstuVWXYZ","0123456789","!\"#$%&'()*+,-./:;<=>?@"
        };
    std::array<std::uniform_int_diStribution<int>,characterTypes.size()> characterTypeDiStributions;
    std::uniform_int_diStribution<int> typeDiStribution{0,characterTypes.size() - 1};
    std::mt19937 eng{std::random_device{}()};

    std::string generate(int numberOfCharacters){
        std::uniform_int_diStribution<int> dist{0,5};
        std::string @R_607_5747@d;
        @R_607_5747@d.reserve(numberOfCharacters);
        for (int i = 0; i < numberOfCharacters; i++)
        {
            auto type = typeDiStribution(eng);
            @R_607_5747@d += characterTypes[type][characterTypeDiStributions[type](eng)];
        }
        return @R_607_5747@d;
    }
};

int main(){
    int @R_607_5747@dLength = 12;
    @R_607_5747@dGenerator gen;
    std::string @R_607_5747@d = gen.generate(@R_607_5747@dLength);
    std::cout << @R_607_5747@d << "\n";
    return 0;
}

请注意，此代码可能仍不符合生成密码的高安全标准。