⑴ 用java计算一个矩形的面积

//计算矩形的面积
public class RectArea {
public static double getArea(double width, double higth) {
double area = 0.0;// 矩形面积
// 判断输入是否合理
if (!(width <= 0 || higth <= 0)) {
area = width * higth;
return area;// 返回面积
} else {
System.out.println("请输入合理的长宽");
return -1;
}
}

public static void main(String[] args) {
//测试 宽:10.0 高:20.0
System.out.println("矩形面积" + RectArea.getArea(10.0, 20.0));
}
}

⑵ java类求N个图形的面积和

楼主,程序如下:

测试类:

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class ShapeSystem {

static List<Shape> sList = new ArrayList<Shape>();
static float square = 0;
public static void main(String[] args) {
while(true)
{
show();
}
}
public static void show()
{
print("***图形类对象的管理***", 1);
print("-------------------", 1);
print("1.创建一个圆", 1);
print("2.创建一个矩形", 1);
print("3.创建一个长方体", 1);
print("4.创建一个圆柱体", 1);
print("5.显示已经创建的图形", 1);
print("6.求各图形的面积之和", 1);
print("7.退出系统", 1);

print("请选择操作项:", 2);
Scanner scanner = new Scanner(System.in);
int action = 0;

try {
action = scanner.nextInt();
} catch (RuntimeException e) {
print("输入必须是整数!", 1);
}

float pi = 3.14f;
String name = "";
float x;
float y;
float h;
float r;
switch (action) {
case 1:
print("请输入圆的名称:", 2);
name = scanner.next();
print("请输入圆心x坐标:", 2);
x = scanner.nextInt();
print("请输入圆心y坐标:", 2);
y = scanner.nextInt();
print("请输入圆的半径:", 2);
r = scanner.nextFloat();

Circle c = new Circle(name,x,y,r);
sList.add(c);
square += pi*r*r;
break;
case 2:
print("请输入矩形的名称:", 2);
name = scanner.next();
print("请输入矩形的长:", 2);
x = scanner.nextInt();
print("请输入矩形的宽:", 2);
y = scanner.nextInt();

Rectangle ra = new Rectangle(name,x,y);
sList.add(ra);
square += x*y;
break;
case 3:
print("请输入长方体的名称:", 2);
name = scanner.next();
print("请输入长方体的长:", 2);
x = scanner.nextInt();
print("请输入长方体的宽:", 2);
y = scanner.nextInt();
print("请输入长方体的高:", 2);
h = scanner.nextInt();
Cube cb = new Cube(name,x,y,h);
sList.add(cb);
square += 2*x*y + 2*x*h +2*h*y;
break;
case 4:
print("请输入圆柱体的名称:", 2);
name = scanner.next();
print("请输入圆柱体的底圆心x坐标:", 2);
x = scanner.nextInt();
print("请输入圆柱体的底圆心y坐标:", 2);
y = scanner.nextInt();
print("请输入圆柱体的底圆的半径:", 2);
r = scanner.nextFloat();
print("请输入圆柱体的高:", 2);
h = scanner.nextFloat();
Clinder ccd = new Clinder(name,x,y,r,h);
sList.add(ccd);
square += 2*pi*r*h;
break;
case 5:
for(Shape s : sList)
{
print(s.getName(), 1);
}
break;
case 6:
print("各图形的面积和为:"+square, 1);
break;
case 7:
print("系统退出...", 1);
System.exit(0);
break;

default:
print("无效的操作项...", 1);
break;
}

}

public static void print(String info,int flag)
{
if(flag == 1)
{
System.out.println(info);
}
else
{
System.out.print(info);
}
}
}

=========================华丽的分割线=============================

图形Shape类:

public abstract class Shape {
private String name;

public Shape(String name)
{
this.name = name;
}
public abstract void show();
public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}
}

=========================华丽的分割线=============================

矩形类:

public class Rectangle extends Shape {

private float x;
private float y;
public Rectangle(String name,float x,float y) {
super(name);
this.x = x;
this.y = y;
}

@Override
public void show() {
System.out.println(this.getName());
}

public String toString()
{
return this.getName() + ":长=" + this.x + " 宽=" + this.y;
}

public float getX() {
return x;
}

public void setX(float x) {
this.x = x;
}

public float getY() {
return y;
}

public void setY(float y) {
this.y = y;
}
}

}

=========================华丽的分割线=============================

长方体为:

public class Cube extends Rectangle {
private float h;
public Cube(String name,float x,float y,float h) {
super(name,x,y);
this.h = h;
}

@Override
public void show() {
System.out.println(this.getName());
}

public String toString()
{
return this.getName() + ":长=" + this.getX() + " 宽=" + this.getY() + " 高=" + this.h;
}
}

=========================华丽的分割线=============================

圆:

public class Circle extends Shape {

private float x;
private float y;
private float r;
public Circle(String name, float x, float y, float r) {
super(name);
this.x = x;
this.y = y;
this.r = r;
}

@Override
public void show() {
System.out.println(this.getName());
}


public float getX() {
return x;
}

public void setX(float x) {
this.x = x;
}

public float getY() {
return y;
}

public void setY(float y) {
this.y = y;
}

public float getR() {
return r;
}

public void setR(float r) {
this.r = r;
}

public String toString()
{
return this.getName() + ":圆心x=" + this.x + " y=" + this.y + " 半径=" + this.r;
}
}

=========================华丽的分割线=============================

圆柱体:

public class Clinder extends Circle {

private float h;
public Clinder(String name, float x, float y, float r,float h) {
super(name, x, y, r);
this.h = h;
}
@Override
public void show() {
System.out.println(this.getName());
}
public String toString()
{
return this.getName() + ":圆心x=" + this.getX() + " y=" + this.getY() + " 半径=" + this.getR() + " 高=" + this.h;
}
}

程序运行效果图:

具体请自行运行程序操作,细节部分需自己完善。

有问题欢迎提问,满意请点赞!有分就加点,谢谢!

⑶ 如何用java定义方法求圆的面积

定义一个方法,参数为半径r,返回面积。代码如下:

publicclassTest(){
publicdoublegetArea(doubler){
doublearea=Math.PI*r*r;
returnarea;
}
publicstaticvoidmain(String[]args){
Testt=newTest();
Scannerscanner=newScanner(System.in);
System.out.print("请输入半径:");
Stringstr=scanner.nextLine();
doubler=Double.parseDouble(str);//将输入的半径转为double类型
doublearea=t.getArea(r);
System.out.print("圆的面积为:"+area);
}
}

⑷ java中怎么求三角形的面积

我记得数学中有个公式的,利用三条边来求的

已知三角形三边a,b,c,半周长p,则S= √[p(p - a)(p - b)(p - c)] (海伦公式)(p=(a+b+c)/2)

⑸ java求几何图形面积

代码如下:

abstractclassGeometry{
abstractdoublegetArea();
}

//三角形
classTriangleextendsGeometry{

//边
privatedoublea;

//边
privatedoubleb;

//边
privatedoublec;

publicTriangle(doublea,doubleb,doublec){
this.a=a;
this.b=b;
this.c=c;
}

@Override
doublegetArea(){

doublep=(a+b+c)/2;

returnMath.sqrt(p*(p-a)*(p-b)*(p-c));
}
}

//圆
classCircleextendsGeometry{

//半径
privatedoubler;

publicCircle(doubler){
this.r=r;
}

@Override
doublegetArea(){
returnMath.PI*r*r;
}
}

//梯形
classLadderextendsGeometry{

//上底
privatedoublea;

//下底
privatedoubleb;

//高
privatedoubleh;

publicLadder(doublea,doubleb,doubleh){
this.a=a;
this.b=b;
this.h=h;
}

@Override
doublegetArea(){
return(a+b)*h/2;
}
}

classTest{
doublecomputeGeometryArea(Geometryg){
returng.getArea();
}
}

publicclassDemo{
publicstaticvoidmain(String[]args){

Testtest=newTest();

Triangletriangle=newTriangle(3,4,6);
System.out.println("三角形面积:"+test.computeGeometryArea(triangle));

Circlecircle=newCircle(10);
System.out.println("圆面积:"+test.computeGeometryArea(circle));

Ladderladder=newLadder(10,20,15);
System.out.println("梯形面积:"+test.computeGeometryArea(ladder));
}
}

运行结果:

⑹ Java 求面积

因为你写了 getArea2=1/2*t2*Math.sqrt((t2*t2)-(1/4*t2*t2));

这里1 / 2两个都是整数,计算等于0。
1 / 4也等于0。
改成
getArea2 = 0.5*t2*Math.sqrt((t2*t2)-(0.25*t2*t2));

就可以了

⑺ 用java编写程序求三角形的面积

构成三角形的条件,要根据任意两边和要大于第三边。代码如下:

import java.util.Scanner;

public class woo {

public static void main(String args[]) {

Scanner scan =new Scanner(System.in);

System.out.println("输入三角形的三边");

int a = scan.nextByte();

int b = scan.nextByte();

int c = scan.nextByte();

float s =(a+b+c)/2f;

float S = (float) Math.sqrt(s*(s-a)*(s-b)*(s-c));

if (a+b>c && b+c>a && a+c>b){

System.out.println(S);

}

else{

System.out.println("不构成三角形");

}

}

}

(7)java求面积扩展阅读

三角形是由同一平面内不在同一直线上的三条线段‘首尾’顺次连接所组成的封闭图形,在数学、建筑学有应用。

常见的三角形按边分有普通三角形(三条边都不相等),等腰三角(腰与底不等的等腰三角形、腰与底相等的等腰三角形即等边三角形);按角分有直角三角形、锐角三角形、钝角三角形等,其中锐角三角形和钝角三角形统称斜三角形。

三角形在平面上三角形的内角和等于180°,在平面上三角形的外角和等于360° ,在平面上三角形的外角等于与其不相邻的两个内角之和。

⑻ 用java计算长方形的面积

// 父类Sharp 如下:public abstract class Sharp {
// 定义面积方法
public abstract double area();
} // 子类RectSharp 继承父类:public class RectSharp extends Sharp { private double width, heigth; public RectSharp(double width, double heigth) {
this.width = width;
this.heigth = heigth;
} /**
* 求出面积
*/
@Override
public double area() {
return width * heigth;
} public static void main(String[] args) {
// 创建一个长方形类
RectSharp r = new RectSharp(100, 50.2);
// 计算面积
double area = r.area();
System.out.println("该长方形的面积为:" + area);
}
}

⑼ java面积计算

MyExam4.java
class MyExam4{
double a,b,c;
MyExam4(){}
MyExam4(double aa,double bb,double cc){}
a=aa;
b=bb;
c=cc;
double returnABC()
{
double s==(a+b+c)/2;
return (s(s-a)(s-b)(s-c))*1/2;
}
}

⑽ Java编程求矩形的面积

代码如下:

import java.util.*;

public class Rectangle {

private float length; //定义长变量

private float width; // 宽变量

public Rectangle(float length,float width){

this.length=length;

this.width=width;

}

public float getGirth(){

return (length+width)*2;

} //求周长方法

public float getArea(){

return length*width;

} //求面积方法

public static void main (String[] args) {

Scanner in=new Scanner(System.in);//调用输入方法

System.out.println ("请输入矩形的长:");

float a=in.nextFloat();

System.out.println ("请输入矩形的宽:");

float b=in.nextFloat();

System.out.println ("矩形周长为:"+new Rectangle(a,b).getGirth());

System.out.println ("矩形面积为:"+new Rectangle(a,b).getArea());

}

}