of its coordinates of its vertices
#include 
#include 
#include 
#include
void main()
{
 float x1,y1,x2,y2,x3,y3;
 float a,b,c,m1,m2,m3;
 clrscr();
 printf("Enter coordinates of vertex A(x & y respectively):- ");
 scanf("%f%f",&x1,&y1);
 printf("
Enter coordinates of vertex B(x & y respectively):- ");
 scanf("%f%f",&x2,&y2);
 printf("
Enter coordinates of vertex C(x & y respectively):- ");
 scanf("%f%f",&x3,&y3);
 if ((x1==x2 && x2==x3)||(y1==y2 && y2==y3))
 {
 printf("
These coordinates can't represent a triangle.");
 printf("
A,B & C are colinear & thus consitute a line.");
 getch();
 exit(0);
 }
 else
 {
 m1=(y2-y1)/(x2-x1);
 m2=(y3-y2)/(x3-x2);
 m3=(y3-y1)/(x3-x1);
 }
 if (m1==m2||m2==m3||m3==m1)
 {
 printf("
These coordinates can't represent a triangle.");
 printf("
A,B & C are colinear & thus consitute a line.");
 printf("
			HAVE A NICE DAY! BYE.");
 getch();
 exit(0);
 }
 a = sqrt(pow((x2-x3),2) + pow((y2-y3),2));
 b = sqrt(pow((x3-x1),2) + pow((y3-y1),2));
 c = sqrt(pow((x2-x1),2) + pow((y2-y1),2));
 printf("
Length of side AB is = %f",c);
 printf("
Length of side BC is = %f",a);
 printf("
Length of side CA is = %f",b);
 if (a==b==c)
 printf("
Triangle made by these vertices is an equilateral triangle.");
 else if (a==b||b==c||c==a)
 {
	if (a==b==c);
 else
	printf("
Triangle made by these vertices is an isosceles triangle.");
 }
 else if (a!=b && b!=c && c!=a)
	printf("
Triangle made by these vertices is a scalene triangle.");
 getch();
}