double isatriangle(double side1, double side2, double side3);
double perim(double side1, double side2, double side3);
double semiper(double side1, double side2, double side3);
double area(double side1, double side2, double side3);


#include<fstream.h>
#include<iostream.h>
#include<math.h>
#include<iomanip.h>


void main()

{

	double side1, side2, side3;
	double answer;
	double sum;
	double halfSum;
	double areaAns;

	ifstream infile("c:\\in_file.txt");
	ofstream outfile("c:\\out_file.txt");

	outfile<<"\n\n\n\n\n"<<endl;
	outfile<<"Sides"<<setw(23)<<"Triangle"<<setw(13)<<"Perimeter"<<setw(7)<<"Area\n"<<endl;
	infile>>setprecision(2)>>setiosflags(ios::fixed | ios::showpoint)>>side1>>side2>>side3;

while(side1 && side2 && side3 !=0.0)
{

	outfile<<setprecision(2)<<setiosflags(ios::fixed | ios::showpoint)<<side1<<" "<<setw(5)<<side2<<" "<<setw(5)<<side3;

        answer = isatriangle(side1, side2, side3);

        if(answer == 1)
          outfile<<setw(11)<<"Triangle";
        else
          outfile<<setw(14)<<"Not a Triangle"<<endl;


        if(answer == 1){	
	  sum = perim(side1, side2, side3);
	  outfile<<setw(13)<<sum;
	
	  halfSum = semiper(side1, side2, side3);
	
	  areaAns = area(side1, side2, side3);
	  outfile<<setw(8)<<areaAns<<setprecision(2)<<setiosflags(ios::fixed | ios::showpoint)<<endl;
        }
	infile>>setprecision(2)>>setiosflags(ios::fixed | ios::showpoint)>>side1>>side2>>side3;
        }

infile.close();
outfile.close();
return;
}