IntegerSet in C ++

I'm having problems with the appointment. Purpose - to create an IntegerSet IntegerSet is an array of 100 elements that represents numbers from 0 to 99, for example, if the number 5 is in the set a, then the a[5] = 1empty set is an array of zeros.

I created an IntegerSet class and here is the code in integerSet.cpp

#include "integerset.h"
#include <iostream>
using std::cout;
using std::endl;

IntegerSet::IntegerSet(){
    int temp[100] = {0};
    set = temp;
}

IntegerSet::IntegerSet(int * setPtr) {
    set = setPtr;
}

void IntegerSet::insertElement(int toInsert) {
    if(toInsert < 100 && toInsert >= 0) {
        set[toInsert] = 1;
    }
}

void IntegerSet::deleteElement(int toDelete) {
    if (toDelete < 100 && toDelete >= 0 ) {
        set[toDelete] = 0;
    }
}

IntegerSet * IntegerSet::unionOfSets(IntegerSet * otherPtr) {
    int newSet[100] = {0};
    for(int i = 0; i < 100; i++ ) {
        if (this->set[i] == 1 || otherPtr->set[i] == 1) {
            newSet[i] = 1;
        }
    }
    return new IntegerSet(newSet);
}

IntegerSet * IntegerSet::intersectionOfSets(IntegerSet* otherPtr) {
    int newSet[100] = {0};
    for(int i = 0; i < 100 ; i++) {
        if(this->set[i] == 1 && otherPtr->set[i] == 1){
            newSet[i] = 1; 
        }
    }
    return new IntegerSet(newSet);
}

bool IntegerSet::isEmpty(){
    for(int i = 0 ; i < 100 ; i++) {
        if(set[i] == 1) {
            return false;
        }
    }
    return true;
}  

bool IntegerSet::isEqualTo(IntegerSet * otherPtr) {
    for(int i = 0; i < 100 ; i++) {
        if(this->set[i] != otherPtr->set[i]) {
            return false;                
        }        
    }
    return true;
}

void IntegerSet::printSet() {
    if(isEmpty()) {
        cout << "---" << endl;
    } else { 
        for(int i = 0; i < 100 ; i++) {
            if(set[i] == 1) {
                cout << i << ' ';
            }
        }
        cout << endl;        
    }
}   

IntegerSet::~IntegerSet() { 
    delete[] set;
}     

The class has a private member int * set;.

This is the main function used to test my class:

#include <iostream>
#include<new>
#include "integerset.h"

using std::cout;
using std::endl;

int main(int argc, char *argv[])
{
    IntegerSet * set1Ptr = new IntegerSet();
    set1Ptr->insertElement(1);
    set1Ptr->insertElement(2);
    set1Ptr->insertElement(3);
    set1Ptr->insertElement(50);
    IntegerSet * set2Ptr = new IntegerSet();
    set2Ptr->insertElement(0);
    set2Ptr->insertElement(3);
    set2Ptr->insertElement(2);
    set2Ptr->insertElement(51);
    set2Ptr->insertElement(100);
    set2Ptr->insertElement(99);
    IntegerSet * set3Ptr = set1Ptr->unionOfSets(set2Ptr);
    IntegerSet * set4Ptr = set1Ptr->intersectionOfSets(set2Ptr);
    cout << "First Set" << endl;
    set1Ptr->printSet();
    cout << "Second Set" << endl;
    set2Ptr->printSet();
    cout << "Equal ? : " << set1Ptr->isEqualTo(set2Ptr) << endl;
    cout << "Intersection : " << endl;
    set4Ptr->printSet();
    cout << "Union : " << endl;
    set3Ptr->printSet();
    system("PAUSE");
    return EXIT_SUCCESS;
}

I get this output at startup

First Set
16 19 35 45 46 54 66 84
Second Set
0 1 10 12 13 14 19 35 45 46 54 66 84
Equal ? : 1
Intersection :
16 19 35 45 46 54 66 84 98
Union :
0 1 10 12 13 14 19 35 45 46 54 66 84 98

I tried tracking, and I have no idea what's wrong, so any help is really appreciated.