Qt使用示例:

QString random_string(int length=32, QString allow_symbols=QString("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")) {
    QString result;
    qsrand(QTime::currentTime().msec());
    for (int i = 0; i < length; ++i) {            
        result.append(allow_symbols.at(qrand() % (allow_symbols.length())));
    }
    return result;
}

让我们再次让随机变得方便!

我做了一个很好的c++ 11头解决方案。 您可以轻松地将一个头文件添加到项目中，然后将测试添加到项目中，或者将随机字符串用于其他目的。

这是一个快速的描述，但是您可以通过链接查看完整的代码。解决方案的主要部分是在Randomer类中:

class Randomer {
    // random seed by default
    std::mt19937 gen_;
    std::uniform_int_distribution<size_t> dist_;

public:
    /* ... some convenience ctors ... */

    Randomer(size_t min, size_t max, unsigned int seed = std::random_device{}())
        : gen_{seed}, dist_{min, max} {
    }

    // if you want predictable numbers
    void SetSeed(unsigned int seed) {
        gen_.seed(seed);
    }

    size_t operator()() {
        return dist_(gen_);
    }
};

随机封装所有随机的东西，你可以很容易地添加自己的功能。有了Randomer之后，生成字符串就很容易了:

std::string GenerateString(size_t len) {
    std::string str;
    auto rand_char = [](){ return alphabet[randomer()]; };
    std::generate_n(std::back_inserter(str), len, rand_char);
    return str;
}

在下面写下你的改进建议。 https://gist.github.com/VjGusev/e6da2cb4d4b0b531c1d009cd1f8904ad

//C++ Simple Code
#include <bits/stdc++.h>
using namespace std;
int main() {
vector<char> alphanum =
    {'0','1','2','3','4',
'5','6','7','8','9',
'A','B','C','D','E','F',
'G','H','I','J','K',
'L','M','N','O','P',
'Q','R','S','T','U',
'V','W','X','Y','Z',
'a','b','c','d','e','f',
'g','h','i','j','k',
'l','m','n','o','p',
'q','r','s','t','u',
'v','w','x','y','z'
};
string s="";
int len=5;
srand(time(0)); 
for (int i = 0; i <len; i++) {
    int t=alphanum.size()-1;
    int idx=rand()%t;
    s+= alphanum[idx];
}
cout<<s<<" ";
return 0;
}

 void gen_random(char *s, size_t len) {
     for (size_t i = 0; i < len; ++i) {
         int randomChar = rand()%(26+26+10);
         if (randomChar < 26)
             s[i] = 'a' + randomChar;
         else if (randomChar < 26+26)
             s[i] = 'A' + randomChar - 26;
         else
             s[i] = '0' + randomChar - 26 - 26;
     }
     s[len] = 0;
 }

Mehrdad Afshari的回答可以解决这个问题，但我觉得对于这个简单的任务来说，它有点太啰嗦了。查询表有时可以创造奇迹:

#include <ctime>
#include <iostream>
#include <unistd.h>

std::string gen_random(const int len) {
    static const char alphanum[] =
        "0123456789"
        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
        "abcdefghijklmnopqrstuvwxyz";
    std::string tmp_s;
    tmp_s.reserve(len);

    for (int i = 0; i < len; ++i) {
        tmp_s += alphanum[rand() % (sizeof(alphanum) - 1)];
    }
    
    return tmp_s;
}

int main(int argc, char *argv[]) {
    srand((unsigned)time(NULL) * getpid());     
    std::cout << gen_random(12) << "\n";        
    return 0;
}

注意rand生成的随机数质量很差。

我希望这能帮助到一些人。

在https://www.codechef.com/ide上用c++ 4.9.2测试

#include <iostream>
#include <string>
#include <stdlib.h>     /* srand, rand */

using namespace std;

string RandomString(int len)
{
   string str = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
   string newstr;
   int pos;
   while(newstr.size() != len) {
    pos = ((rand() % (str.size() - 1)));
    newstr += str.substr(pos,1);
   }
   return newstr;
}

int main()
{
   srand(time(0));
   string random_str = RandomString(100);
   cout << "random_str : " << random_str << endl;
}

输出: random_str: DNAT1LAmbJYO0GvVo4LGqYpNcyK3eZ6t0IN3dYpHtRfwheSYipoZOf04gK7OwFIwXg2BHsSBMB84rceaTTCtBC0uZ8JWPdVxKXBd