pdslab/day0/cs1713-day0-prog2.c

/*
 * Copyright (C) 2020, 2019, 2018, 2017 Girish M
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301, USA.
 * 
 */
/*-----------------------------------
Name: Girish M
Roll number: MTech CS 13
Date: 20/07/2017
Program description: Calculate area of triangle using coordinates
Acknowledgements: Hero's formula
------------------------------------*/
#include <stdio.h>
#include <math.h>

float areaTriangle(float []);
const unsigned length = 6;
int main(void)
{
	float cdn[length];
	unsigned i;
	printf("\nEnter 3 coordinates of triangle (x1,y1), (x2,y2) and (x3,y3)\n");
	for(i=0; i<length; i++)
	{
	  scanf("%f", &cdn[i]);
	}
	printf("\nThe area of triangle is: %.3f\n", areaTriangle(cdn));
	return 0;
}

/*Ar. triangle = 1/2 * (x1(y2-y3)-y1(x2-x3)+(x2*y3-y2*x3))*/

float areaTriangle(float cdn[])
{
	return fabs((0.5*(cdn[0]*(cdn[3]-cdn[5])-(cdn[1]*(cdn[2]-cdn[4]))+(cdn[2]*cdn[5]-cdn[3]*cdn[4]))));
}