(Stringpermutations) Write a recursive function to print all permutations of a string. For...

(Stringpermutations) Write a recursive function to print all permutations of a string. For example, for a string abc , the permutation is

abc

acb

bac

bca

cab

cba

(Hint:Define the following two functions. The second is a helper function.)void displayPermuation(const string& s)

void displayPermuation(const string& s1, const string& s2)

The first function simply invokes displayPermuation("", s). The second function uses a loop to move a character from s2 to s1 and recursively invoke it with a new s1 and s2. The base case is that s2 is empty and prints s1 to the console.

Write a test program that prompts the user to enter a string and displays all its permutations.