BPA C++ Competition Practice

//include libraries and namespaces
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <vector>
#include <string>

using namespace std;

//Outputs the first 20 fibonacci numbers
void generateFibonacci()
{
    int fibonacci[20], current, next, previous;
    current = 1;
    previous = 0;
    for(int i = 0; i < 20; i++)
    {
        fibonacci[i] = current;
        previous = current;
        current += previous;
    }
    for(int i = 0; i < 20; i++)
    {
        cout << fibonacci[i] << " ";
        if(i == 19)
        {
            cout << endl;
        }
    }


}
//Outputs all perfect numbers less than or equal to 1000
void generatePerfectNumbers()
{
    vector<int> perfectNumbers;
    for(int i =0; i < 1000; i++)
    {   vector<int> divisors;
        for(int n = 1; n < i - 1; n++)
        {
            if(n % i == 0)
            {
                divisors.push_back(n);
            }
        }
        int divisorSum = 0;
        for(int x = 0; x < divisors.size()-1; x++)
        {
            divisorSum += divisors[x];
        }
        if(divisorSum == i)
        {
            perfectNumbers.push_back(i);
        }
    }
    for(int i = 0; i < perfectNumbers.size(); i++)
    {
        cout << perfectNumbers[1] << " ";
        if(i == perfectNumbers.size() -1)
        {
            cout << endl;
        }
    }
}

int main()
{   char response;
    int validResponses[3] = {1, 2, 3};
    do
    {
        cout << "***************\nSpecial Number Generator\n***************" << endl << "1) Generate Fibonacci Numbers\n2) Generate Perfect Numbers\n3) Exit Program"<< endl;


        cout << "Select an option :";
        cin >> response;
        switch(response)
        {
            case '1' :
                generateFibonacci();
                break;

            case '2' :
                generatePerfectNumbers();
                break;

            case '3' :
                break;

            default :
                cout << "Invalid Response\n";

        }

    }
    while (response != '3');

    return 0;
    }