Advanced C Programming
                                           Spring 2004


Exercise 2 (Pointers and parameters)



	Write a program that first reads three integers. Then the
        program finds out whether it is possible to construct
        a triangle, whose side lengths are indicated by the numbers 
        just entered. It it is possible to construct a triangle, 
        the program calculates the area of the triangle and at the 
        end displays that area. 

        You have to divide the program in separate peaces using 
        functions and you have to use parameters to pass
        information to and from the functions. Because the main 
        goal of the exercise is to learn to use pointer parameters 
        when needed, let's agree that we don't use "return-method"
        to return results to the caller ( not even in the function, 
        that finds out whether the triangle can be constructed or
        not). This means that all functions should be in the form 
 
              void f(parameter list ...);


        The functions you have to write are 
              read three numbers
              can triangle be constructed
              calculate area
              display area
        

	Hint. The area of a triangle can be calculated using the Heron's
        formula:
                                                      
	       A = sqrt ((p/2)*(p/2 - a)*(p/2 - b)*(p/2 - c))
                


	where p = a + b + c and a, b and c are the lenghts of the sides.