In this tutorial, i am going to show you how to find sum of lower triangle matrix in c programs.

## Algorithm to Find Sum of Lower Triangle Matrix

Follow the below given algorithm to write a program to find or calculate sum of lower triangle matrix; as follows:

- Start program.
- Declare an M*N 2D array.
- Initialize the array.
- If the number of rows and columns are not equal then it is not possible to display the sum of the elements of the lower triangle.
- If the number of rows is equal to the number of columns, then proceed for the calculation of lower triangular elements.
- Using two for loops traverse through the elements.
- If (i>=j), then add all the elements.
- Display the final result.
- Stop program.

## C Program to Find Sum of Lower Triangle Matrix

#include<stdio.h> int main() { int i, j, rows, columns, a[10][10], Sum = 0; printf("\n Please Enter Number of rows and columns : "); scanf("%d %d", &i, &j); printf("\n Please Enter the Matrix Elements \n"); for(rows = 0; rows < i; rows++) { for(columns = 0;columns < j;columns++) { scanf("%d", &a[rows][columns]); } } for(rows = 0; rows < i; rows++) { for(columns = 0; columns < j; columns++) { if(rows > columns) { Sum = Sum + a[rows][columns]; } } } printf("\n The Sum of Lower Triangle Matrix = %d", Sum); return 0; }

The result of the above c program; as follows:

Please Enter Number of rows and columns : 3 3 Please Enter the Matrix Elements 1 2 3 4 5 6 7 8 9 The Sum of Lower Triangle Matrix = 19