Program that gives all details of a Triangle given the lengths of its sides.

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
#include<math.h>

main()
{
clrscr();
float a,b,c,S,D,A,B,C,Area,R;
printf("Enter the lengths of the three sides of the triangle :");
scanf("%f%f%f",&a,&b,&c);
S = (a+b+c)/2.0; // S is the semiperimeter of the triangle
D = S*(S-a)*(S-b)*(S-c);//D is the square of the area of the triangle
if(D<=0)
{
printf("The triangle cannot be formed");
getch();
exit(0);
}

if((a==b || b==c || c==a) && !(a==b && b==c && c==a))
// this complex logic is to eliminate interpretting a triangle with all
three
// sides equal as both isosceles and equilateral.
printf("The triangle is ISOSCELES");
if(a==b && b==c && c==a)
printf("The triangle is EQUILATERAL");
if(a!=b && b!=c && c!=a)
printf("The triangle is SCALENE");

Area = sqrt(D);
R = (a*b*c)/(4.0*Area);
printf("PERIMETER = %.2f units",(2.0*S));
printf("AREA = %.2f sq.units",Area);
printf("CIRCUM RADIUS = %.2f units",R);
// using sine rule,we get...
A = (180.0/3.1415926)*asin(a/(2.0*R));// value of pi should be upto 7
B = (180.0/3.1415926)*asin(b/(2.0*R));// decimal places of accuracy and
also
C = (180.0/3.1415926)*asin(c/(2.0*R));// note that the 7th decimal place
is
// 6 and not 7 as it had to be if were
if(A==90.0 || B==90.0 || C==90.0) // approximated to 7 decimal
places
printf("The triangle is RIGHT ANGLED");
if(A<90.0 && B<90.0 && C<90.0)
printf("The triangle is ACUTE ANGLED");
if(A>90.0 || B>90.0 || C>90.0)
printf("The triangle is OBTUSE ANGLED");

printf("The angles are as follows :");
printf("A = %.2f degrees",A);
printf("B = %.2f degrees",B);
printf("C = %.2f degrees",C);
printf("Where A,B,C stand for angles opposite to sides %.2f,%.2f,%.2f",a,b,c);
printf(" respectively");

getch();
return 0;
}