Java 类和对象7

创建一个三角形类，成员变量三边，方法求周长，创建类主类A来测试它。

 public class sanjiaoxing {

     private double a;
     private double b;
     private double c;
     double zhouchang;

     public double getA() {
         return a;
     }

     public void setA(double a) {
         this.a = a;
     }

     public double getB() {
         return b;
     }

     public void setB(double b) {
         this.b = b;
     }

     public double getC() {
         return c;
     }

     public void setC(double c) {
         this.c = c;
     }

     sanjiaoxing(double a, double b, double c) {
         this.a = a;
         this.b = b;
         this.c = c;
     }

     public void getZhouChang() {
         zhouchang = 0;
         if ((a + b > c && a + c > b && b + c > a) && (a >= 0 && b >= 0 && c >= 0)) {
             zhouchang = a + b + c;
         } else {
             System.out.println(this.a + "\t" + this.b + "\t" + this.c  + "三个数不能构成三角形。");
         }
         if (zhouchang != 0) {
             System.out.println(this.a + "\t" + this.b + "\t" + this.c  + "三个数成功构成三角形 ，周长=" + zhouchang);
         }
     }

     public static void main(String[] args) {
         sanjiaoxing s1 = new sanjiaoxing(1.4, 2.5, 3);
         s1.getZhouChang();

         sanjiaoxing s2 = new sanjiaoxing(1, 3, 4);
         s2.getZhouChang();

         sanjiaoxing s3 = new sanjiaoxing(1, 5, 5);
         s3.getZhouChang();

         sanjiaoxing s4 = new sanjiaoxing(3, -4, 5);
         s4.getZhouChang();
     }

运行：