Project 1 of week 5: triangle (default constructor and constructor with parameters)

/** Program Copyright and version description Section * copyright (c) 2012, Yantai University Computer college student * All rightsreserved. * Author: Li Yang * Completion Date: July 15, March 31, 2013 * version: V1.0 * input Description: none * Problem description: none * program output: none */# include <iostream> # include <cmath> using namespace STD; Class triangle {public: Double perimeter (void); // calculate the triangle perimeter double area (void ); // calculate and return the Triangle Area void showmessage (); triangle (Double X, Double Y, Double Z); Private: Double A, B, C; // The three sides are private member data}; triangle: triangle () {A = 1; B = 1; C = 1;} triangle: triangle (Double X, double y, double Z) {A = x; B = y; C = z;} double triangle: Perimeter () {return (A + B + C);} double triangle :: area () {double S; S = (A + B + C)/2; Return (SQRT (S * (S-A) * (S-B) * (s-c);} void triangle: showmessage () {cout <"Triangle's three sides are: "<A <" "<B <" "<C <Endl; cout <" the circumference of the triangle is: "<perimeter () <" <"Area:" <area () <Endl;} void main (void) {triangle tri1; // defines an instance (object) of the triangle class. A default constructor is required. The initial values of the three sides are 1tri1. showmessage (); triangle tri2 (7,8, 9); tri2.showmessage ();}