Write a program that checks whether a matrix is a lower triangular matrix.

A matrx is said to be a lower triangular matrix if all values above the main diagonal are zeros.

#include <stdio.h>
#include <conio.h>
#define SIZE 50
void main()
{
	int A[SIZE][SIZE];
	int R, C;        /* dimensions */
	int I, J;

	do {
		printf("Number of rows   (max.%d) : ", SIZE);
		scanf("%d", &R);
	} while (R <= 0 || R > SIZE);
	do {
		printf("Number of columns (max.%d) : ", SIZE);
		scanf("%d", &C);
	} while (C <= 0 || C > SIZE);

	printf("*** Matrix ***\n");
	for (I = 0; I<R; I++)
		for (J = 0; J<C; J++)
		{
			printf("A[%d][%d] : ", I, J);
			scanf("%d", &A[I][J]);
		}

	// check if the matrix is a lower triangular matrix
	for (I = 0; I < R; I++)
	{
		// we check elements greater than I
		for (J = I+1; J < R; J++)
			if (A[I][J] != 0) // if one element is not zero, exit the inner loop
				break;
		if (J < R) // either we have exited the inner loop normally (J==R), nothing to do , we continue
			break;	// otherwise, we exited the loop because if the break, so we need to exit the outer loop too 
	}

	if (I == R)
		printf("The matrix is a Lower triangular matrix.\n");
	else
		printf("The matrix is not a Lower triangular matrix.\n");


	getch();
}