2D array values C++

The proper way to initialize a multidimensional array in C or C++ is

int arr[2][5] = {{1,8,12,20,25}, {5,9,13,24,26}};

You can use this same trick to initialize even higher-dimensional arrays if you want.

Also, be careful in your initial code - you were trying to use 1-indexed offsets into the array to initialize it. This didn't compile, but if it did it would cause problems because C arrays are 0-indexed!

int iArray[2][2] = {{1, 2}, {3, 4}};

Think of a 2D array as an array of arrays.

Just want to point out you do not need to specify all dimensions of the array.

The leftmost dimension can be 'guessed' by the compiler.

#include <stdio.h>
int main(void) {
  int arr[][5] = {{1,2,3,4,5}, {5,6,7,8,9}, {6,5,4,3,2}};
  printf("sizeof arr is %d bytes\n", (int)sizeof arr);
  printf("number of elements: %d\n", (int)(sizeof arr/sizeof arr[0]));
  return 0;
}

Like this:

int main()
{
    int arr[2][5] =
    {
        {1,8,12,20,25},
        {5,9,13,24,26}
    };
}

This should be covered by your C++ textbook: which one are you using?

Anyway, better, consider using std::vector or some ready-made matrix class e.g. from Boost.