Program to crack a 4 character password

[vipertherapper]

Hey, I'm attempting to use the function CrackP to try all possible combinations of "AAAA" through "ZZZZ" until CrackP's output equals P. I'd like a nudge in the right direction. Here's my current code:

#include <iostream>
#include <string>
#include <ctime>

using namespace std;

string GenChar(int length)
{
    string res;
    for (int i = 0; i < length; i++)
    {
        res += 'A' + (rand() % 26);
    }
    return res;
}
void CrackP(string P) {
    string crackAttempt = GenChar(4);
    cout << "Target: " + P << endl;
    cout << "Attempting to crack...";

    while (crackAttempt != P) {
        crackAttempt = GenChar(4);

    }

    if (crackAttempt == P) {
        cout << "Cracked " + crackAttempt;
    }
    

}
int main()
{
    string P;
    srand((unsigned)time(nullptr));
    P = GenChar(4);
    CrackP(P);
}

What should I do from here?

[Thomas1965]

This will give you all combination from "AA" to "ZZ".
Maybe you can adapt it to your needs.

  string s("  ");

  for (char c1 = 'A'; c1 <= 'Z'; c1++)
    for (char c2 = 'A'; c2 <= 'Z'; c2++)
    {
      s[0] = c1;
      s[1] = c2;
      cout << s << "\n";
    }

[vipertherapper]

Thomas, that's exactly what I needed. I've adapted it to the following:

        for (char c1 = 'A'; c1 <= 'Z'; c1++)
            for (char c2 = 'A'; c2 <= 'Z'; c2++)
                for (char c3 = 'A'; c3 <= 'Z'; c3++)
                    for (char c4 = 'A'; c4 <= 'Z'; c4++) {
                        s[0] = c1;
                        s[1] = c2;
                        s[2] = c3;
                        s[3] = c4;

                        cout << s << endl;


                    }


    }

My question is this: how can I run the for loops only until s = P?

For example, if P is AAAZ, I want to stop the execution of the for loops. I also want to print the number of iterations or attempts it took to "crack" the password.

I tried enclosing the for loops in

while ( s != P ), but that doesn't work because s is an empty string until later on in the loop.

Any suggestions?

[AbstractionAnon]

Simply return from the function when you find a match.

void CrackP (const string & P) 
{   string s; 
    int attempts = 0;
    
    for (char c1 = 'A'; c1 <= 'Z'; c1++)
        for (char c2 = 'A'; c2 <= 'Z'; c2++)
            for (char c3 = 'A'; c3 <= 'Z'; c3++)
                for (char c4 = 'A'; c4 <= 'Z'; c4++) 
                {   s[0] = c1;
                    s[1] = c2;
                    s[2] = c3;
                    s[3] = c4;
                    attempts++;
                    if (s == P) 
                    {   cout << "Cracked " + crackAttempt;
                        cout << " in " << attempts << " attempts " << endl;
                        return;
                    }
                }
}

BTW, there is a much more efficient way to do this by checking one character at a time. i.e. Don't enter the second loop until you've found a match on the first loop.

void CrackP (const string & p) 
{   for (char c1 = 'A'; c1 <= 'Z'; c1++)
        if (p[0] == c1)
            for (char c2 = 'A'; c2 <= 'Z'; c2++)
                if (p[1] == c2)
                    for (char c3 = 'A'; c3 <= 'Z'; c3++)
                        if (p[2] == c3)
                            for (char c4 = 'A'; c4 <= 'Z'; c4++) 
                                if (p[3] == c4)
                                {   cout << "Cracked " << p << endl;                                    
                                    return;
                                }
                
}

[lastchance]

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#include <iostream> #include <vector> #include <string> #include <cmath> using namespace std; const string ALPHABET = "ABC"; // For testing // const string ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; // For real const int CHOICES = ALPHABET.size(); //====================================================================== void nextWord( vector<int> &Iword ) // The next word (as defined by character indices) { for ( int i = 0; i < Iword.size(); i++ ) { if ( Iword[i] < CHOICES - 1 ) // If can increment this position, do so and return { Iword[i]++; return; } else // Otherwise cycle back and continue to next position { Iword[i] = 0; } } } //====================================================================== string word( vector<int> &Iword ) { string result = ""; for ( int i : Iword ) result += ALPHABET[i]; return result; } //====================================================================== int main() { int N = 4; // Intended length of password vector<int> Iword( N, 0 ); int MAXWORDS = pow( CHOICES, N ); cout << word( Iword ) << endl; for ( int w = 2; w <= MAXWORDS; w++ ) { nextWord( Iword ); cout << word( Iword ) << endl; } } //======================================================================

AAAA BAAA CAAA ABAA BBAA CBAA ACAA BCAA CCAA AABA BABA CABA ABBA BBBA CBBA ACBA BCBA CCBA AACA BACA CACA ABCA BBCA CBCA ACCA BCCA CCCA AAAB BAAB CAAB ABAB BBAB CBAB ACAB BCAB CCAB AABB BABB CABB ABBB BBBB CBBB ACBB BCBB CCBB AACB BACB CACB ABCB BBCB CBCB ACCB BCCB CCCB AAAC BAAC CAAC ABAC BBAC CBAC ACAC BCAC CCAC AABC BABC CABC ABBC BBBC CBBC ACBC BCBC CCBC AACC BACC CACC ABCC BBCC CBCC ACCC BCCC CCCC