where to go from here

[ascii]

im solving a programming challenge where you have to devise a program to print out every possible combination of the letters in a string. the mini algorithm i have for the program will essentially switch every letter with every other letter, and is written rougly like so (copyarray is a copy of the original string)

array[0] = array[0 + 1];
array[0 + 1] = copyarray[0]

all of the constants in this will be replaced by variables of course :)

however when im going through each character eventually adding numbers will cause it to go out of bounds of the array and give me some random crap when i output the string. how might i go about avoiding this?

[hamsterman]

do %string_length.
Though I'm not sure I understand the problem. Do you need to find every permutation of a given string? Now you're just rotating it..

[ascii]

trying to find every permutation, and ive already used strlen.
what do you mean by just rotating it? if i have the word dog for example replacing the numbers with the letters of the word it would end up like this

array[d] = array[o]
array[o] = array[d]

so the word would end up as odg
right..?

[hamsterman]

Oh. I guess it;s fine then.
I meant

int len = strlen(array);
array[i] = array[ (i + 1)%len];
array[(i + 1)%len] = copyarray[i]

That way i+1 won't be out of bounds. It there something else? Post the whole loop in that case.

[ascii]

#include <iostream>
#include <cstring>
using std::cout;
using std::endl;
using std::cin;

int main(void)
{
	const int max = 10;
	char str[max] = {0};
	char copystr[max] = {0};
	cout << "String: ";
	cin >> str;
	int length = strlen(str);

	//make a copy of the string
	for (int i = 0; i < length; i++)
		copystr[i] = str[i];

	for (int i = 0; i < length; i++)
	{	
		//swap characters
		for (int y = 0; y < length; y++)
		{
			str[i] = str[(i + y) % length];
			str[(i + y) % length] = copystr[i];
		}

		cout << str << endl;
		//reset the string
		for (int i = 0; i < length; i++)
			str[i] = copystr[i];
	}

	cout << str << endl;
	return 0;
}

obviously it doesnt work so help please :)

[hamsterman]

doesn't work, as in doesn't permute correctly, or keeps going out of bounds?

Either way, there is http://www.cplusplus.com/reference/algorithm/next_permutation/

Also, in case you haven't tried, google should give you plenty of solutions. It's a rather popular task..

[ascii]

well the point is that im trying to do it without googling it because i dont really see how ill get better if i just copy some code..?

and doesnt work as in doesnt permute correctly

[ultifinitus]

Hey! This was one of my favorite problems to work on!! Did you see my blog post on it?

[ascii]

didnt know you had ablog lol, but im near giving up on this and just working on my bubble sortting program instead anyhow :o