Altering the Properties of Pointer Objects

[Liuqahs15]

Hello everyone, I'm new to this forum and C++

I'm writing a program that will let you create a faux database. Basically I want to use dynamic memory to let users create arrays of objects with properties they define.

I've run into an issue that I don't fully understand, though, so I thought I'd ask for a little help : )

I want to declare an object as a pointer (because later I'll make the object into a new array with a variable in its index), and let the user change the value of one of the properties. Here's the code:

#include <iostream>
#include <string>

using namespace std;

        struct props{
            char numval[10];
            char altval[10];
        };

    class DataObj{
        public:

            props * numprop;//this will become an array which contains properties that house number values

            char DataName[10];//the name of the data can't be longer than 10 letters//

            props * altprop;//this will become an array which contains the different properties.
    };

int main()
{

        cout << "Type in the name of the objects you want to collect data on(for example, \'Books\' or \'Cars\')\n\n\t";

        DataObj * Entry;

        cin >> (*Entry).DataName;

//the code goes on from here, but this is where the runtime error occurs.//

So is it just that you can't change the properties of a pointer? It compiles perfectly. It's just that a runtime error crashes it after the user changes the value of the DataName property.

[hamsterman]

Entry doesn't point to anything yet. Either allocate an object with new or assign an address of some object to it.

[Liuqahs15]

That worked! Thanks a lot : D