Question

I want to initialize values of 2-D array to 0. But it seems not to work.
Can I initialize values of my **array in constructor to be 0. If yes the How.
My code is.

#include <iostream>
using namespace std;

int main(){
int row, col;
cin>>row;
cin>>col;
int **array=new int*[row];
        for (int i=0; i<row; i++){
            array[i]=new int[col];
        }
            for (int i=0; i<row;i++){
                for (int j=0; j<col; j++){
                    array[i][j]={'0'};
                    cout<<array[i][j]<<" ";
                }
                cout<<endl;
            }

}

Further can someone explain if I have to replace ith elem from the array with some other element, how would I deal with memory allocation.

Answer 1

You probably want array[i][j]=0;. Why were you using the char type '0'?
However, there is an easier way: array[i]=new int[col]();, just add () to value initialize each column.

There also is a better way:

std::vector<std::vector<int>> array(row, std::vector<int>(col));

For your first comment, you would need to create a new array with the new size, copy over all the data, and the delete your old 2-d array.

For your second comment, here is an example:

struct A
{
    int **array;
    A(int row, int col) : array(new int*[row])
    {
       for (int i=0; i < row; i++)
       {
          array[i]=new int[col]();
       }
    }
};

PS: You can save yourself a lot of work by using std::vector.