Password Cracker

#include <iostream>
#include <string>
#include <sstream>
#include <stdlib.h>
#include <thread>
#include <cstdio>
#include <ctime>

std::string password; //DO NOT ACCESS
bool cracked = false;
std::string legalChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890!@#$%^&*()_";
std::string crackedPassword;

int countChar(std::string str, char c)
{
    int rtn = 0;
    for(unsigned i = 0; i < str.length(); i++)
    {
        if(str[i] == c)
        {
            rtn++;
        }
    }
    return rtn;
}

std::string charToString(char c)
{
    std::stringstream ss;
    std::string target;
    ss << c;
    ss >> target;
    return target;
}

int testFirstChar(char c)
{
    std::string toTest = charToString(c);
    if(toTest == password)
    {
        cracked = true;
        crackedPassword = toTest;
        return 1;
    }
    else
    {
        bool doneTwo;
        bool doneThr;
        bool doneFou;
        for(int i = 0; i < 73; i++)
        {
            doneTwo = false;
            for(int j = 0; j < 73; j++)
            {
                doneThr = false;
                for(int k = 0; k < 73; k++)
                {
                    doneFou = false;
                    for(int l = 0; l < 73; l++)
                    {
                        if(cracked)
                        {
                            return 1;
                        }

                        toTest = charToString(c) + charToString((char) legalChars[i]);
                        if(!doneTwo)
                        {
                            if(toTest == password)
                            {
                                cracked = true;
                                crackedPassword = toTest;
                                return 1;
                            }
                            doneTwo = true;
                        }

                        toTest += charToString((char) legalChars[j]);
                        if(!doneThr)
                        {
                            if(toTest == password)
                            {
                                cracked = true;
                                crackedPassword = toTest;
                                return 1;
                            }
                            doneThr = true;
                        }

                        toTest += charToString((char) legalChars[k]);
                        if(!doneFou)
                        {
                            if(toTest == password)
                            {
                                cracked = true;
                                crackedPassword = toTest;
                                return 1;
                            }
                            doneFou = true;
                        }

                        toTest += charToString((char) legalChars[l]);
                        if(toTest == password)
                        {
                            cracked = true;
                            crackedPassword = toTest;
                            return 1;
                        }
                    }
                }
            }
        }
    }
    std::cout << "oh well" << std::endl;
}

void testFirstChars(std::string str)
{
    for(unsigned i = 0; i < str.length(); i++)
    {
        if(!cracked)
        {
            int crack = testFirstChar((char) str[i]);
            if(crack == 1)
            {
                break;
            }
        }
    }
}

int main() {
    std::clock_t start;
    double duration;
    start = std::clock();

    bool acceptPassword = true;
    std::cout << "Please input a password. Maximum length is 5 characters. Alphanumeric characters and !@#$%^&*()_ only." << std::endl;
    std::cin >> password;
    if(password.length() > 5)
    {
        acceptPassword = false;
    }
    else
    {
        for(unsigned i = 0; i < password.length(); i++)
        {
            char cur = (char) password[i];
            if(countChar(legalChars, cur) == 0)
            {
                acceptPassword = false;
            }
        }
    }
    while(!acceptPassword)
    {
        acceptPassword = true;
        std::cout << "Invalid password. Please try again." << std::endl;
        std::cout << "Please input a password. Maximum length is 5 letters. Permitted characters: Letters (upper and lower case); !@#$%^&*()_" << std::endl;
        std::cin >> password;
        if(password.length() > 5)
        {
            acceptPassword = false;
        }
        else
        {
            for(unsigned i = 0; i < password.length(); i++)
            {
                char cur = password[i];
                if(countChar(legalChars, cur) == 0)
                {
                    acceptPassword = false;
                }
            }
        }
    }
    std::cout << "Working. Please wait for completion." << std::endl;

    std::thread t1(testFirstChars, "ABCDEFGH1");
    std::thread t2(testFirstChars, "IJKLMNOP2");
    std::thread t3(testFirstChars, "QRSTUVWX3");
    std::thread t4(testFirstChars, "YZabcdef4");
    std::thread t5(testFirstChars, "ghijklmn5");
    std::thread t6(testFirstChars, "opqrstuv6");
    std::thread t7(testFirstChars, "wxyz!@#$7");
    std::thread t8(testFirstChars, "%^&*()_890");
    t1.join();
    t2.join();
    t3.join();
    t4.join();
    t5.join();
    t6.join();
    t7.join();
    t8.join();

    duration = (std::clock() - start) / ((double) CLOCKS_PER_SEC);
    std::cout << "Cracked password: " + crackedPassword << std::endl;
    std::cout << " in " + std::to_string(duration) + "ms." << std::endl;
    return 0;
}