Print all the permutations of the given string

December 27, 2021

Print all permutations of a string

Today in this article we will learn how to print all the permutations of a string using C Programming language.

If the length of the string is n then the total number of permutation is n!. 

Lets understand this with the help of an example:- 

  • Input sting:- abc
  • Output:- abc,acb,bac,bca,cba,cab.
Print all permutations of a string
All Permutations of a String

Algorithm

  • Step 1 : Take the string which you need to check if the string is palindrome or not.
  • Step 2 : Calculate the length of the string. Let the length of the string be n 
  • Step 3 : make a function CheckPalindrome() which will take string as parameter
  • Step 4:- initialize low and high index and assign low with 0 and high with length-1
  • Step 5:  Keep comparing characters while they are same
  • Step 6:- if the comparison is true for every case then print its palindrome else not palindrome

C++ Code :-

Method 1

  // C++ program to print all permutations with duplicates allowed 
  #include <bits/stdc++.h> 
  using namespace std;

  // Function to swap values at two pointers 
  void swap(char *x, char *y) 
  { 
   char temp; 
   temp = *x; 
   *x = *y; 
   *y = temp; 
  }

  void permute(char *a, int l, int r) 
 { 
   int i; 
   if (l == r) 
    cout<<a<<endl; 
   else
   { 
    for(i = l; i <= r; i++) 
     { 
     swap((a+l), (a+i)); 
     permute(a, l+1, r); 
     swap((a+l), (a+i)); //backtrack 
     } 
   } 
}

// Driver program to test permute functions
 int main() 
{ 
   char str[1000] ; 
   cout<<"Enter the string :";
   gets(str);

   cout<<"All the permutations of the string :";
   int n = strlen(str); 
   permute(str, 0, n-1); 
 
   return 0; 
 }

Output:-

Enter the string :abv
All the permutations of the string :abv
avb
bav
bva
vba
vab
Enter the string :abcf
All the permutations of the string :abcf
abfc
acbf
acfb
afcb
afbc
bacf
bafc
bcaf
bcfa
bfca
bfac
cbaf
cbfa
cabf
cafb
cfab
cfba
fbca
fbac
fcba
fcab
facb
fabc