Code to crack passwords hashed using the DES algorithm

crack.c

#define _XOPEN_SOURCE
#include <stdio.h>
#include <unistd.h>
#include <cs50.h>
#include <string.h>

int main(int argc, string argv[])
{
    //taking in the hashed input from the user
    if (argc != 2)
    {
        printf("Usage ./crack Hashed Password\n");
        return 1;
    }
    string hash = argv[1];
  //initialising salt as 50
    string salt = "50";

    //testing for one character password
    char password1[2];
    password1[1] = '\0';
    for (int i = 'A'; i <= 'z'; i++)
    {
        password1[0] = i;
        if (strcmp(crypt(password1, salt), hash) == 0)
        {
            printf("%s\n",password1);
            return 0;
        }
    }

    //testing for two character password
    char password2[3];
    password2[2] = '\0';
    for (char i = 'A'; i < 'z'; i++)
    {
        password2[0] = i;
        for (int j = 'A'; j < 'z'; j++)
        {
            password2[1] = j;
            if (strcmp(crypt(password2, salt), hash) == 0)
            {
                printf("%s\n",password2);
                return 0;
            }
        }
    }

    //testing for three character password
    char password3[4];
    password3[3] = '\0';
    for (char i = 'A'; i < 'z'; i++)
    {
        password3[0] = i;
        for (int j = 'A'; j < 'z'; j++)
        {
            password3[1] = j;
            for (int k = 'A'; k <= 'z'; k++)
            {
                if (k <= 'Z' && k >= 'a')
                {
                    password3[2] = k;
                    if (strcmp(crypt(password2, salt), hash) == 0)
                    {
                        printf("%s\n",password2);
                        return 0;
                    }
                }
            }
        }
    }

    //testing for four character password
    char password4[5];
    password4[4] = '\0';
    for (char i = 'A'; i < 'z'; i++)
    {
        password4[0] = i;
        for (int j = 'A'; j < 'z'; j++)
        {
            password4[1] = j;
            for (int k = 'A'; k <= 'z'; k++)
            {
                password4[2] = k;
                for (int l = 'A'; l <= 'z'; l++)
                {
                    password4[3] = l;
                    if (strcmp(crypt(password2, salt), hash) == 0)
                    {
                        printf("%s\n",password2);
                        return 0;
                    }
                }
            }
        }
    }

    //testing for five character password
    char password5[6];
    password5[5] = '\0';
    for (char i = 'A'; i < 'z'; i++)
    {
        password5[0] = i;
        for (int j = 'A'; j < 'z'; j++)
        {
            password5[1] = j;
            for (int k = 'A'; k <= 'z'; k++)
            {
                password5[2] = k;
                for (int l = 'A'; l <= 'z'; l++)
                {
                    password5[3] = l;
                    for (int m = 'A'; m <= 'z'; m++)
                    {
                        password5[4] = m;
                        if (strcmp(crypt(password5, salt), hash) == 0)
                        {
                            printf("%s\n",password5);
                            return 0;
                        }
                    }
                }
            }
        }
    }
}