How Can I Generate Random Alpha-Numeric Strings in C ?

Generating Random Alpha-Numeric Strings in C

Creating random strings consisting of alpha-numeric characters is a common task in programming. In C , there are several approaches to achieve this, each with its advantages and limitations.

One straightforward approach is to make use of look-up tables and the rand() function to generate a random index within the table. Here's an example:

#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;
}

This code demonstrates how random alpha-numeric strings can be generated by simply referencing a look-up table and selecting characters based on random indexes. It is concise and easy to implement.

However, it's important to note that the rand() function generates pseudo-random numbers, which may not be suitable for applications requiring true randomness. For higher quality random number generation, consider using a dedicated library like boost::random.

The above is the detailed content of How Can I Generate Random Alpha-Numeric Strings in C ?. For more information, please follow other related articles on the PHP Chinese website!