Brute Force Character Generation in C++ - c++

Question

So I'm trying to make a brute force string generator to match and compare strings in CUDA. Before I start trying to mess around with a language I don't know I wanted to get one working in C++. I currently have this code.
#include <iostream>
#include <string>
#include <cstdlib>
using namespace std;
int sLength = 0;
int count = 0;
int charReset = 0;
int stop = 0;
int maxValue = 0;
string inString = "";
static const char charSet[] = //define character set to draw from
"0123456789"
"!##$%^&*"
"abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ";
int stringLength = sizeof(charSet) - 1;
char genChars()
{
return charSet[count]; //Get character and send to genChars()
}
int main()
{
cout << "Length of string to match?" << endl;
cin >> sLength;
cout << "What string do you want to match?" << endl;
cin >> inString;
string sMatch(sLength, ' ');
while(true)
{
for (int y = 0; y < sLength; y++)
{
sMatch[y] = genChars(); //get the characters
cout << sMatch[y];
if (count == 74)
{
charReset + 1;
count = 0;
}
if (count == 2147000000)
{
count == 0;
maxValue++;
}
}
count++;
if (sMatch == inString) //check for string match
{
cout << endl;
cout << "It took " << count + (charReset * 74) + (maxValue*2147000000) << " randomly generated characters to match the strings." << endl;
cin >> stop;
}
cout << endl;
}
}
Now this code runs and compiles but it doesn't exactly do what I want it to. It will do 4 of the same character, EX. aaaa or 1111 and then go onto the next without incrementing like aaab or 1112. I've tried messing around with things like this
for (int x = 0; x < sLength; x++)
{
return charSet[count-sLength+x];
}
Which in my mind should work but to no avail.

Answer 1

You basically just need to increment a counter, than convert the count number to base (size of char array)
Here's an example which does normal numbers up to base 16.
http://www.daniweb.com/code/snippet217243.html
You should be able to replace
char NUMS[] = "0123456789ABCDEF";
with your set of characters and figure it out from there. This might not generate a large enough string using a uint, but you should be able to break it up into chunks from there.
Imagine your character array was "BAR", so you would want to convert to a base 3 number using your own symbols instead of 0 1 and 2.
What this does is perform a modulus to determine the character, then divide by the base until the number becomes zero. What you would do instead is repeat 'B' until your string length was reached instead of stopping when you hit zero.
Eg: A four character string generated from the number 13:
14%3 = 2, so it would push charSet[2] to the beginning of the empty string, "R";
Then it would divide by 3, which using integer math would = 4. 4%3 is again 1, so "A".
It would divide by 3 again, (1) 1%3 is 1, so "A".
It would divide by 3 again, (0) -- The example would stop here, but since we're generating a string we continue pushing 0 "B" until we reach 4 our 4 characters.
Final output: BAAR
For an approach which could generate much larger strings, you could use an array of ints the size of your string, (call it positions), initialize all the ints to zero and do something like this on each iteration:
i = 0;
positions[i]++;
while (positions[i] == base)
{
positions[i] = 0;
positions[++i]++;
}
Then you would go through the whole array, and build the string up using charSet[positions[i]] to determine what each character is.