Recursive Enumeration Example, C++ (clang)

Recursive Enumeration Example

// Example from Lecture 6 in class on recursive functions

#include <iostream>
using namespace std;

void recursiveEnumeration(int *array, int start, int n) 
{
    static int permutationNumber = 0;
    for (int i=0; i<start; i++) cout << "   ";
    cout << "Entering into recursiveEnumeration level:  start = " << start << endl;
    if (start==(n-1)) {
        // print out answer
        for (int i=0; i<n; i++) {
            cout << "   ";
        }
        cout << "** Permutation Number: " << ++permutationNumber << " is: ";
        for (int i=0; i<n; i++) {
            cout << array[i] << " ";
        }
        cout << "**" << endl;
        return;
    }
    for (int i=start; i<n; i++) {
        // make recursive call, note the change of the argument values
        // need to do swap here...
        recursiveEnumeration(array,start+1,n);
        // need to undo swap here...
    }
    for (int i=0; i<start; i++) cout << "   ";
    cout << "Returning from recursiveSort level:  start = " << start << endl;
    return;
}

int main()
{
    int n, *array;
    cout << "Enter n: ";
    cin >> n;
    // create array of that size
    array = new int[n];
    cout << endl << "n = " << n << endl << endl;
    cout << "Initial array = ";
    for (int i=0; i<n; i++) {
        array[i] = i+1;
        cout << array[i] << " ";
    }
    cout << endl;
    recursiveEnumeration(array, 0, n);

cout << endl << "Done " << endl;  
    return 0;
}


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