Question

So I am trying to understand two things:

1. What are the differences between these three expressions?
2. What is the equivalent to the first expression (A)?

Here is the code (fixed):

#include "stdafx.h"

void someFunc(double** pArray, int length)
{
    for(int i = 0; i < length; i++)
    {
        //this works perfectly
        double expressionA = *(*pArray + i);
        //this crashes : Unhandled exception at 0x00da13ff in pptrtest.exe: 0xC0000005: Access violation reading location 0xcccccccc.
        double expressionB = **(pArray + i);
        //this crashes : Unhandled exception at 0x00da13ff in pptrtest.exe: 0xC0000005: Access violation reading location 0xcccccccc.
        double expressionC = *pArray[i];
    }
}
int main()
{
    double arr[] = { 1, 2, 3, 4, 5 };

    double* pArr = arr;

    someFunc(&pArr, sizeof arr / sizeof arr[0]);

    return 0;
}

Answer 1

I think the problem is, that [] is applied before *, so in expr C you are doing

*(ppDoubleArray[i])

actually the equivalent of expr B, but the expr A does

(*ppDoubleArray)[i]

(assuming the 1 in the expression should be an i, otherwise thats different anyway).