C++ console closes immediately, possibly crashing (cin, system("pause"), etc. have no effect)

Question

I've got the bare shell of a program with a "BasicObject" class and a randum number generator class implemented. When I run the program, the console closes immediately, and cin functions, system("pause"), etc. have no effect. I suspect a crash, but can't find what the source might be. Any help?

BaseObject.cpp:

#include "BaseObject.h"
#include "RandNumGenerator.h"

#include <iostream>
#include <string>

using namespace std;

BaseObject::BaseObject() {

    RandNumGenerator* numGen;
    set_id(numGen->generate_randNum_str(5));
    delete numGen;

}

BaseObject::~BaseObject() {}

...

//void - sets value of string "id"
void BaseObject::set_id(string newId) {

    id = newId;

}

Here's the main function:

#include <iostream>
#include <string>

#include "BaseObject.h"

using namespace std;

int main() {

    string userIn = "";
    BaseObject* obj;

    while (userIn != "q") {

        cout << "Id of \"obj\" is " << obj->get_id() << endl;
    
        cout << endl << "Type 'q' to quit." << endl;
        cin >> userIn;

    }

    return 0;

}

Answer 1

It's crashing, because here

obj->get_id() 

obj is not initializated yet. Just a pointer to memory with some random garbage.

You need something like

BaseObject* obj = new BaseObject()

Before you can use obj