Why do pass by pointer function works if we simply pass the variables please guide

Question

I was practising with C++ Pointers and trying different things and came to know about this thing:

The Variables number 1 and number 2 does not has the address they stores integer but the function swap wants two pointers But this works...

But it should only give the answer with the & or pointers. Why This happens and if this is valid then what we call it?

Kindly guide Me!!!!

Complete Code is:

    #include<iostream>
using namespace std;

void swap (int *, int *);


int main()
{
    int number_1 =0;
    int number_2=0;
    
    cout<<"Please Enter The First Number : ";
    cin>>number_1;
    
    cout<<"Please Enter The Second Number : ";
    cin>>number_2;
    
    
    int *ptr_number_1=&number_1;
    int *ptr_number_2=&number_2;
    

    
    cout<<"Before The Function Call Numbers Are : "<<endl;
    cout<<"Number 1 Contains : " << number_1<<endl;
    cout<<"Number 2 Contains : " << number_2<<endl;
    
    cout<<"=================================="<<endl;
    cout<<"Calling the Function with the direct variables : "<<endl;
    cout<<"After The Function Call Numbers Are : "<<endl;
    swap (number_1,number_2);
    cout<<"Number 1 Contains : " << number_1<<endl;
    cout<<"Number 2 Contains : " << number_2<<endl;
    cout<<endl;
    cout<<"=================================="<<endl;
    
    cout<<"=================================="<<endl;
    cout<<"Calling the Function with the Reference Operator : "<<endl;
    cout<<"After The Function Call Numbers Are : "<<endl;
    swap (&number_1,&number_2);
    cout<<"Number 1 Contains : " << number_1<<endl;
    cout<<"Number 2 Contains : " << number_2<<endl;
     cout<<endl;
    cout<<"=================================="<<endl;
    
    cout<<"=================================="<<endl;
    cout<<"Calling the Function with the Pointers  : "<<endl;
    cout<<"After The Function Call Numbers Are : "<<endl;
    swap (ptr_number_1,ptr_number_2);
    cout<<"Number 1 Contains : " << number_1<<endl;
    cout<<"Number 2 Contains : " << number_2<<endl;
     cout<<endl;
    cout<<"=================================="<<endl;
    
    
    

    cout<<endl;
    return 0;
}

void swap (int *number_1, int *number_2){
    
    int temp_number_variable =0;
    temp_number_variable = *number_2;
    *number_2 = *number_1;
    *number_1 = temp_number_variable;
    
}