C++ program to find sum of lower triangular matrix

Write a C++ program to find the sum of a lower triangular matrix?

How to find the sum of a lower triangular matrix (2D- 2 Dimensional Array) in C++. Logic to find the sum of the lower triangular matrix in C++ programming.
Write a C++ program to read elements in a matrix(2D- 2 Dimensional Array) and find the sum of a lower triangular matrix.

Logic

Program

#include<iostream>
using namespace std;
#define max_rows 3
#define max_cols 3
int main()
{
	int a[max_rows][max_cols];
	int row,col,sum=0;
	cout<<"Please enter elements of matrix of given size"<<max_rows<<"x"<<max_cols<<endl;
	for(row=0; row<max_rows ;row++)
	{
		for(col=0;col<max_cols;col++)
		{
			cin>>a[row][col];
		}
	}
	for(row=0; row<max_rows ;row++)
	{
		for(col=0;col<max_cols;col++)
		{
			cout<<a[row][col];
		}
		cout<<endl;
	}
	for(row=0;row<max_rows;row++)
	{
		for(col=0;col<max_cols;col++)
		{
			if(col<row)
			{
				sum+=a[row][col];
			}
		}
	}
	cout<<"sum of lower triangular matrix="<<sum;
}

Output