Print 2D matrix in C++

#include<iostream>
using namespace std;
int main()
{
    int a , b , c=0 , i=0 , j;
    cout << "Enter length and width of the matrix" << endl;
    cout << "Length = ";
    cin >> a ;
    cout << "Width = ";
    cin >> b ;
    while (i<a)
    {
        i=i+1;
        j=0;
        cout << endl ;
        while (j<b)
        {
            j=j+1;
            c=c+1;
            if (c%2==1)
            {
                cout << " 0 ";
            }
            else
            {
                cout << " 1 ";
            }
        }
    }
    return 0;
}