163.cpp

// C++ program to print all permutations
// with repetition of characters
#include <bits/stdc++.h>
#include<string.h>
using namespace std;


/* Following function is used by
the library qsort() function
to sort an array of chars */
int compare (const void * a, const void * b);

/* The main function that recursively
prints all repeated permutations of
the given string. It uses data[] to store all
permutations one by one */
void allLexicographicRecur (char *str, char* data,
							int last, int index)
{
	int i, len = strlen(str);

	// One by one fix all characters at
	// the given index and recur for
	// the/ subsequent indexes
	for ( i = 0; i < len; i++ )
	{
		// Fix the ith character at index
		// and if this is not the last
		// index then recursively call
		// for higher indexes
		data[index] = str[i] ;

		// If this is the last index then
		// print the string stored in
		// data[]
		if (index == last)
			cout << data << endl;
		else // Recur for higher indexes
			allLexicographicRecur (str, data, last, index+1);
	}
}

/* This function sorts input string,
allocate memory for data (needed
for allLexicographicRecur()) and
calls allLexicographicRecur() for
printing all permutations */
void allLexicographic(char *str)
{
	int len = strlen (str) ;

	// Create a temp array that will
	// be used by allLexicographicRecur()
	char *data = (char *) malloc (sizeof(char) * (len + 1)) ;
	data[len] = '\0';

	// Sort the input string so that
	// we get all output strings in
	// lexicographically sorted order
	qsort(str, len, sizeof(char), compare);

	// Now print all permutaions
	allLexicographicRecur (str, data, len-1, 0);

	// Free data to avoid memory leak
	free(data);
}

// Needed for library function qsort()
int compare (const void * a, const void * b)
{
	return ( *(char *)a - *(char *)b );
}

// Driver code
int main()
{
	char str[] = "ABC";
	cout << "All permutations with repetition of "<<
								str <<" are: "<<endl ;
	allLexicographic(str);
	return 0;
}