This code prints out all combinations of given string.

permutation.cc

#include <iostream>
using namespace std;

void printAll(const char str[], char buf[], bool used[], int start, int end);
void printAll(const char str[]);

int main(int argc, char* argv[])
{
	if(argc != 2)
	{
		cerr << "Instruction: " << argv[0] << " [string]" << endl;
		return -1;
	}
	printAll(argv[1]);
	return 0;

}

void printAll(const char str[])
{
	int len = strlen(str);
	bool* used = new bool[len];
	memset(used, 0, len);
	char* buf = new char[len+1];
	//strcpy(buf, str);
	buf[len] = '\0';
	printAll(str, buf, used, 0, len);
	free(buf);
	free(used);
}

void printAll(const char str[], char buf[], bool used[], int start, int end)
{
	if(end - start == 0)
	{
		// when permutation ends
		cout << buf << endl;
		return;
	}

	for(int i=0; i<end; ++i)
	{
		// if char at i is used, we pass
		if(used[i])
			continue;

		// if char at i is not used yet, put it in the array
		used[i] = true;
		buf[start] = str[i];
		printAll(str, buf, used, start+1, end);
		// after it recursively print all permutations set the character is not used
		used[i] = false;
	}
}