课后习题page101.pp3.7

//************************************************// triangleArea.java  Author: Jayson //***********************************************import java.util.Scanner;public class triangleArea {//--------------------------------------------------//  input triangle's three side, and //  output its area with Heron Formula//  Heron Formula: area = sqrt(s(s-a)(s-b)(s-c)//  s = (a+b+c) / 2//--------------------------------------------------public static void main(String[] args){double a, b, c, s, area;Scanner scan = new Scanner(System.in);System.out.println("Please input three side of a triangle: ");a = scan.nextDouble();b = scan.nextDouble();c = scan.nextDouble();scan.close();s = (a + b + c) /2 ;area = Math.sqrt(s * (s-a) * (s-b) * (s-c));System.out.println("The area of the triangle is: " + area);}}