我想创建一个随机字符串,由字母-数字字符组成。我希望能够指定字符串的长度。

如何在c++中做到这一点?


当前回答

一些更简单和更基本的东西,如果你想让你的字符串包含任何可打印的字符:

#include <time.h>   // we'll use time for the seed
#include <string.h> // this is for strcpy

void randomString(int size, char* output) // pass the destination size and the destination itself
{
    srand(time(NULL)); // seed with time

    char src[size];
    size = rand() % size; // this randomises the size (optional)

    src[size] = '\0'; // start with the end of the string...

    // ...and work your way backwards
    while(--size > -1)
        src[size] = (rand() % 94) + 32; // generate a string ranging from the space character to ~ (tilde)

    strcpy(output, src); // store the random string
}

其他回答

我的2p解:

#include <random>
#include <string>

std::string random_string(std::string::size_type length)
{
    static auto& chrs = "0123456789"
        "abcdefghijklmnopqrstuvwxyz"
        "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    thread_local static std::mt19937 rg{std::random_device{}()};
    thread_local static std::uniform_int_distribution<std::string::size_type> pick(0, sizeof(chrs) - 2);

    std::string s;

    s.reserve(length);

    while(length--)
        s += chrs[pick(rg)];

    return s;
}

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;
}

随机字符串,每个运行文件=不同的字符串

        auto randchar = []() -> char
    {
        const char charset[] =
            "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
            "abcdefghijklmnopqrstuvwxyz";

        const size_t max_index = (sizeof(charset) - 1);

        return charset[randomGenerator(0, max_index)];
    };
            std::string custom_string;
            size_t LENGTH_NAME = 6 // length of name
    generate_n(custom_string.begin(), LENGTH_NAME, randchar);
//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;
}

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