#include <iostream>
#include <random>
#include <string>
 
std::string generateRandomChar(const unsigned int _len)
    {
        std::string result;
        result.reserve(_len);
 
        static constexpr char alphanum[] = "0123456789"
                                           "abcdefghijklmnopqrstuvwxyz"
                                           "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        std::random_device rd;
        std::mt19937 gen(rd());
 
        for (int i = 0; i < _len; i++) {
            std::uniform_int_distribution<> dis(0, 61);
            result += (alphanum[dis(gen)]);
        }
        return result;
    }
 
int main(){
	for(int i = 0; i < 10; ++i){
		std::cout << generateRandomChar(10) << std::endl;
	}
}

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