Question

I have the following structure:

struct CountCarrier
{
    int *CurrCount;
};

And this is what I want to do:

int main()
{
    CountCarrier carrier = CountCarrier();
    *(carrier.CurrCount) = 2;  // initialize the *(carrier.CurrCount) to 2
    IncreaseCount(&carrier);  // should increase the *(carrier.CurrCount) to 3
}


void IncreaseCount(CountCarrier *countCarrier)
{
    int *currCounts = countCarrier->CurrCount;
    (*currCounts)++;
}

So, my intention is specified in the comments.

However, I couldn’t get this to work. For starters, the program throws an exception at this line:

*(carrier.CurrCount) = 2;

And I suspect the following line won’t work as well. Anything I did wrong?

Answer 1

    struct CountCarrier 
    {     
        int *CurrCount;  //No memory assigned
    }; 

You need to allocate some valid memory to the pointer inside the structure to be able to put data in this.

Unless you do so, What you ar trying to do is attempting to write at some invalid address, which results in an Undefined Behavior, which luckiy in this case shows up as an exception.

Resolution:

    struct CountCarrier 
    {     
        int *CurrCount;  //No memory assigned
        CountCarrier():CurrCount(new(int))
        {

        }
    }; 

Suggestion:
Stay away from dynamic allocations as long as you can.
When you think of using pointers always think whether you really need one. In this case it doesn’t really seem that you need one, A simple int member would be just fine.