三角形面积计算代码：
package edu.jmi.shape;
import java.util.Scanner;
public class Sanjiaoxing extends Shape{
private float a;//私有属性，除该类外，其他地方均不能直接访问
private float b;
private float c;
private float h;
//计算并返回周长，输入：无，返回：周长值
public float zhouChang(){
float zhou = a+b+c;
return zhou;
}
public float mianJi(){
float mian = (a*h)/2;
return mian;
}
//读取输入，计算并显示结果
void handle(){
//1 提示
System.out.println("请输入三角的三条边长和高");
//2 读取输入
Scanner sc = new Scanner(System.in);
a = sc.nextFloat();
b = sc.nextFloat();
c = sc.nextFloat();
h = sc.nextFloat();
//计算
float zhou = zhouChang();
float mian = mianJi();
//输出
System.out.println("三角形周长是"+zhou+",面积是"+mian+"");
}
/**
-
@param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Sanjiaoxing san=new Sanjiaoxing();
san.a =6;
san.b =5;
san.c =4;
san.h =4;
System.out.println("请输入三角形的三边长和高：");
Scanner sc = new Scanner(System.in);
san.a= sc.nextFloat();
san.b= sc.nextFloat();
san.c= sc.nextFloat();
san.h= sc.nextFloat();
float zc = san.zhouChang();//通过对象调用周长计算
System.out.println("周长："+zc);
float mj = san.mianJi();
System.out.println("面积："+mj);
}//main}
判断三边是否能成三角形：
package edu.jmi.java1;
import java.util.Scanner;public class Sanjiaoxing {
/**
-
@param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("输入三条边：");
Scanner sc = new Scanner(System.in);
int i = sc.nextInt();
int j = sc.nextInt();
int k = sc.nextInt();
if(i>0 && j>0 && k>0 &&
i+j>k && i+k>j && j+k>i ){
System.out.println("Yes");
}else{
System.out.println("No");
}
}//main}
