allocating two dimensinal array

Question

I have following C++ node

unsigned int uiNoOfItems = 113;
unsigned int W = 2347;

// create two dimensional array

unsigned int ** optimalWeight = new unsigned int* [uiNoOfItems + 1];
for (unsigned int uiRowIdx = 0; uiRowIdx <= uiNoOfItems; uiRowIdx++) {
    optimalWeight[uiRowIdx] = new unsigned int (W + 1);
}


std::cout << " initializing first column "<< std::endl;
// initialize first column
for (unsigned int uiRowIdx = 0; uiRowIdx <= uiNoOfItems; uiRowIdx++) {
    optimalWeight[uiRowIdx][0] = 0;
}

std::cout << " initializing first row "<< std::endl;
// initialize first row
for (unsigned int uiColIdx = 0; uiColIdx <= W; uiColIdx++) {
    // std::cout << uiColIdx << std::endl;
    optimalWeight[0][uiColIdx] = 0; ------------------------> crash happens here at uiColIdx value 1210
}

Above code crash is happening at mentioned line. I am not getting why as memory allocation is successfull.

`new unsigned int (W + 1);` Does **not** create an array of `W + 1` size. Did you mean to write `new unsigned int [W + 1];`? — Algirdas Preidžius, Mar 06 '18 at 09:30
These pointer-to-pointer things are not 2D arrays. See [Correctly allocating multi-dimensional arrays](https://stackoverflow.com/questions/42094465/correctly-allocating-multi-dimensional-arrays) - replace malloc with new and free with delete[] and you get C++. Though of course, preferably use a C++ container class instead. — Lundin, Mar 06 '18 at 09:50

score 1 · Accepted Answer · answered Mar 06 '18 at 09:38

1

You can do it in this way as well

unsigned const int uiNoOfItems = 113;
unsigned const int W = 2347;    

int (*var)[W] = new int[uiNoOfItems][W];

answered Mar 06 '18 at 09:38

Santosh Thapa

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allocating two dimensinal array

1 Answers1