print all the combinations of the digits of a given number

Question

Algorithm to print all the number possible with the digits of a given number

eg :if input is "234",combinations possible are

234,243,324,342,432,423

Comments

Total number of combinations are Factorial N, this is what you are looking or wants to print the numbers also - assuming all distinct digits.

Answer 1

void permute(int a[], int i, int N)
{
        int j;
        if(i == N)
                printf("\n%d%d%d%d",a[0],a[1],a[2],a[3]); 
        else
                for ( j = i; j < N; j++)
                {
                        a[i] = a[i] + a[j] - (a[j] = a[i]);
                        permute(a, i + 1, N);
                        a[i] = a[i] + a[j] - (a[j] = a[i]);
                }
}

int main()
{
        int a[] = {1,2,3,4};
        permute(a,0,4);
        return 0;
}

Comments

Well done Vikas.

Answer 2

Try this (in C++ though u can write it again in C)

#include <iostream>
#include <algorithm>
using namespace std;

void outputArray(int* array, int size)
{
  for (int i = 0; i < size; ++i) { cout << array[i] << " "; }
}

int main ()
{
  int myints[] = { 1, 2, 3, 4, 5 };
  const int size = sizeof(myints);

  cout << "The 5! possible permutations with 5 elements:\n";

  sort (myints, myints + size);

  bool hasMorePermutations = true;
  do
  {
    outputArray(myints, size);
    hasMorePermutations = next_permutation(myints, myints + size);
  }
  while (hasMorePermutations);

  return 0;
}

Comments

where is this function "next_permutation" implemented.