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| author | crupest <crupest@outlook.com> | 2021-04-14 09:20:56 +0800 |
|---|---|---|
| committer | crupest <crupest@outlook.com> | 2021-04-14 09:20:56 +0800 |
| commit | 5e5001a462916fda66fda8996e0fe85f73779a76 (patch) | |
| tree | 9c24f710f1f18728ef84fc76998a84a81c1e0e60 | |
| parent | 80366e378bb4af5b9184e3d1f198f9a86672e394 (diff) | |
| download | crupest-5e5001a462916fda66fda8996e0fe85f73779a76.tar.gz crupest-5e5001a462916fda66fda8996e0fe85f73779a76.tar.bz2 crupest-5e5001a462916fda66fda8996e0fe85f73779a76.zip | |
import(life): Add java practice.
24 files changed, 947 insertions, 0 deletions
diff --git a/works/life/java-practice/.gitignore b/works/life/java-practice/.gitignore new file mode 100644 index 0000000..acec74a --- /dev/null +++ b/works/life/java-practice/.gitignore @@ -0,0 +1,60 @@ +.metadata +bin/ +tmp/ +*.tmp +*.bak +*.swp +*~.nib +local.properties +.settings/ +.loadpath +.recommenders + +# External tool builders +.externalToolBuilders/ + +# Locally stored "Eclipse launch configurations" +*.launch + +# PyDev specific (Python IDE for Eclipse) +*.pydevproject + +# CDT-specific (C/C++ Development Tooling) +.cproject + +# CDT- autotools +.autotools + +# Java annotation processor (APT) +.factorypath + +# PDT-specific (PHP Development Tools) +.buildpath + +# sbteclipse plugin +.target + +# Tern plugin +.tern-project + +# TeXlipse plugin +.texlipse + +# STS (Spring Tool Suite) +.springBeans + +# Code Recommenders +.recommenders/ + +# Annotation Processing +.apt_generated/ +.apt_generated_test/ + +# Scala IDE specific (Scala & Java development for Eclipse) +.cache-main +.scala_dependencies +.worksheet + +# Uncomment this line if you wish to ignore the project description file. +# Typically, this file would be tracked if it contains build/dependency configurations: +#.project diff --git a/works/life/java-practice/javatest/.classpath b/works/life/java-practice/javatest/.classpath new file mode 100644 index 0000000..6bf1eac --- /dev/null +++ b/works/life/java-practice/javatest/.classpath @@ -0,0 +1,10 @@ +<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+ <classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-15">
+ <attributes>
+ <attribute name="module" value="true"/>
+ </attributes>
+ </classpathentry>
+ <classpathentry kind="src" path="src"/>
+ <classpathentry kind="output" path="bin"/>
+</classpath>
diff --git a/works/life/java-practice/javatest/.project b/works/life/java-practice/javatest/.project new file mode 100644 index 0000000..34df9f4 --- /dev/null +++ b/works/life/java-practice/javatest/.project @@ -0,0 +1,17 @@ +<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+ <name>javatest</name>
+ <comment></comment>
+ <projects>
+ </projects>
+ <buildSpec>
+ <buildCommand>
+ <name>org.eclipse.jdt.core.javabuilder</name>
+ <arguments>
+ </arguments>
+ </buildCommand>
+ </buildSpec>
+ <natures>
+ <nature>org.eclipse.jdt.core.javanature</nature>
+ </natures>
+</projectDescription>
diff --git a/works/life/java-practice/javatest/src/javatest/ArrayDemo2.java b/works/life/java-practice/javatest/src/javatest/ArrayDemo2.java new file mode 100644 index 0000000..8d7b2ae --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/ArrayDemo2.java @@ -0,0 +1,13 @@ +package javatest;
+
+public class ArrayDemo2 {
+ public static void main(String args[]) {
+ int score[][] = { { 10, 3 }, { -1, 119, -51 }, { 100, 56, 90, 49 } };
+ for (int i = 0; i < score.length; i++) {
+ for (int j = 0; j < score[i].length; j++) {
+ System.out.print(score[i][j] + "\t");
+ }
+ System.out.println("");
+ }
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/ArrayDemo3.java b/works/life/java-practice/javatest/src/javatest/ArrayDemo3.java new file mode 100644 index 0000000..f053b4b --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/ArrayDemo3.java @@ -0,0 +1,31 @@ +package javatest;
+
+public class ArrayDemo3 {
+ public static void main(String args[]) {
+ int score[] = { 25, 78, 35, 84, 69, 74, 12, 56 };
+ int age[] = { 32, 52, 12, 63, 42, 15, 75, 23, 56 };
+ sort(score); // 调用排序方法
+ print(score); // 调用输出方法
+ System.out.println("\n-----------------------------------------");
+ sort(age);
+ print(age);
+ }
+
+ public static void sort(int temp[]) { // 数组排序
+ for (int i = 1; i < temp.length; i++) { // 冒泡算法
+ for (int j = 0; j < temp.length; j++) {
+ if (temp[i] < temp[j]) {
+ int x = temp[i];
+ temp[i] = temp[j];
+ temp[j] = x;
+ }
+ }
+ }
+ }
+
+ public static void print(int x[]) { // 数组输出
+ for (int i = 0; i < x.length; i++) {
+ System.out.print(x[i] + " , ");
+ }
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/E0201.java b/works/life/java-practice/javatest/src/javatest/E0201.java new file mode 100644 index 0000000..5cda62a --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/E0201.java @@ -0,0 +1,21 @@ +package javatest;
+
+public class E0201 {
+ public static int max(int a, int b) {
+ return a > b ? a : b;
+ }
+
+ public static double max(double a, double b) {
+ return a > b ? a : b;
+ }
+
+ public static int max(int a, int b, int c) {
+ return max(a, max(b, c));
+ }
+
+ public static void main(String[] args) {
+ System.out.println(max(1, 2));
+ System.out.println(max(2.2, 3.3));
+ System.out.println(max(1, 2, 3));
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/E0202.java b/works/life/java-practice/javatest/src/javatest/E0202.java new file mode 100644 index 0000000..c74beec --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/E0202.java @@ -0,0 +1,12 @@ +package javatest;
+
+public class E0202 {
+ public static int F(int n) {
+ if (n == 1 || n == 2) return 1;
+ return F(n - 2) + F(n - 1);
+ }
+
+ public static void main(String[] args) {
+ System.out.println(F(6));
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/E0203.java b/works/life/java-practice/javatest/src/javatest/E0203.java new file mode 100644 index 0000000..7bec46f --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/E0203.java @@ -0,0 +1,26 @@ +package javatest;
+
+public class E0203 {
+ public static void main(String[] args) {
+ int[] array = new int[] { 1, 2, 3, 4 };
+ intArray.printArray(array);
+ System.out.println();
+ intArray.printArray(intArray.reverse(array));
+ }
+}
+
+class intArray {
+ public static void printArray(int[] array) {
+ for (int i = 0; i < array.length; i++) {
+ System.out.print(array[i] + " ");
+ }
+ }
+
+ public static int[] reverse(int[] list) {
+ int[] result = new int[list.length];
+ for (int i = 0; i < list.length; i++) {
+ result[i] = list[list.length - i - 1];
+ }
+ return result;
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/E0204.java b/works/life/java-practice/javatest/src/javatest/E0204.java new file mode 100644 index 0000000..c79e33c --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/E0204.java @@ -0,0 +1,90 @@ +package javatest;
+
+import java.util.HashSet;
+import java.util.Random;
+
+public class E0204 {
+ public static void main(String[] args) {
+ Random r = new Random();
+ HashSet<Card> set = new HashSet<Card>();
+
+ while (set.size() != 4) {
+ set.add(Card.random(r));
+ }
+
+ for (Card card : set) {
+ System.out.println(card);
+ }
+ }
+}
+
+class Card {
+ public static final String[] suits = { "Spades", "Hearts", "Clubs", "Diamonds" };
+ public static final String[] ranks = { "Ace", "2", "3", "4", "5", "6", "7", "8", "9", "10", "Jack", "Queen",
+ "King" };
+
+ public static Card random(Random r) {
+ return new Card(suits[r.nextInt(suits.length)], ranks[r.nextInt(ranks.length)]);
+ }
+
+ public Card(String suit, String rank) {
+ super();
+ this.suit = suit;
+ this.rank = rank;
+ }
+
+ private String suit;
+ private String rank;
+
+ public String getSuit() {
+ return suit;
+ }
+
+ public void setSuit(String suit) {
+ this.suit = suit;
+ }
+
+ public String getRank() {
+ return rank;
+ }
+
+ public void setRank(String rank) {
+ this.rank = rank;
+ }
+
+ @Override
+ public int hashCode() {
+ final int prime = 31;
+ int result = 1;
+ result = prime * result + ((rank == null) ? 0 : rank.hashCode());
+ result = prime * result + ((suit == null) ? 0 : suit.hashCode());
+ return result;
+ }
+
+ @Override
+ public boolean equals(Object obj) {
+ if (this == obj)
+ return true;
+ if (obj == null)
+ return false;
+ if (getClass() != obj.getClass())
+ return false;
+ Card other = (Card) obj;
+ if (rank == null) {
+ if (other.rank != null)
+ return false;
+ } else if (!rank.equals(other.rank))
+ return false;
+ if (suit == null) {
+ if (other.suit != null)
+ return false;
+ } else if (!suit.equals(other.suit))
+ return false;
+ return true;
+ }
+
+ @Override
+ public String toString() {
+ return "Card [suit=" + suit + ", rank=" + rank + "]";
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/Main.java b/works/life/java-practice/javatest/src/javatest/Main.java new file mode 100644 index 0000000..4c4a70c --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/Main.java @@ -0,0 +1,7 @@ +package javatest;
+
+public class Main {
+ public static void main(String[] args) {
+ System.out.println("Hello world!");
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/MethodDemo2.java b/works/life/java-practice/javatest/src/javatest/MethodDemo2.java new file mode 100644 index 0000000..161de5d --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/MethodDemo2.java @@ -0,0 +1,30 @@ +package javatest;
+
+public class MethodDemo2 {
+ public static void main(String args[]) {
+ int one = add(29, 58); // 调用addOne()方法
+ int three = add(25, 58, 10); // 调用addOne()方法
+ float two = add(26.35f, -12.84f); // 调用addTwo()方法
+ System.out.println("add(int x,int y)=" + one);
+ System.out.println("add(int x,int y,int z)=" + three);
+ System.out.println("add(float x,float y)=" + two);
+ }
+
+ public static int add(int x, int y) { // 定义方法，两个整数加法，返回一个整型数据
+ int temp = 0; // temp为局部变量，只在此方法中有效
+ temp = x + y;
+ return temp; // 返回计算结果
+ }
+
+ public static int add(int x, int y, int z) { // 定义方法，两个整数加法，返回一个整型数据
+ int temp = 0; // temp为局部变量，只在此方法中有效
+ temp = x + y + z;
+ return temp; // 返回计算结果
+ }
+
+ public static float add(float x, float y) {
+ float temp = 0;
+ temp = x + y;
+ return temp;
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/e0301/Circle.java b/works/life/java-practice/javatest/src/javatest/e0301/Circle.java new file mode 100644 index 0000000..ec380ec --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/e0301/Circle.java @@ -0,0 +1,33 @@ +package javatest.e0301;
+
+public class Circle {
+ private static int numOfObjects = 0;
+
+ public static int getNumOfObjects() {
+ return numOfObjects;
+ }
+
+ private double radius;
+
+ public Circle(double radius) {
+ this.radius = radius;
+ numOfObjects++;
+ }
+
+ public double getArea() {
+ return radius * radius * Math.PI;
+ }
+
+ public static void printCircle(Circle c) {
+ System.out.println("Radius of circle is " + c.radius);
+ System.out.println("Area of circle is " + c.getArea());
+ }
+
+ public static void main(String[] args) {
+ Circle c1 = new Circle(2);
+ Circle c2 = new Circle(3);
+ Circle.printCircle(c1);
+ Circle.printCircle(c2);
+ System.out.println("Num of objects is " + Circle.getNumOfObjects());
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/e0302/Rational.java b/works/life/java-practice/javatest/src/javatest/e0302/Rational.java new file mode 100644 index 0000000..772cf12 --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/e0302/Rational.java @@ -0,0 +1,45 @@ +package javatest.e0302;
+
+public class Rational {
+ private long numerator;
+ private long denominator;
+
+ private static long gcd(long a, long b) {
+ return b != 0 ? gcd(b, a % b) : a;
+ }
+
+ public Rational(long numerator, long denominator) {
+ long d = gcd(numerator, denominator);
+ this.numerator = numerator / d;
+ this.denominator = denominator / d;
+ }
+
+ public Rational add(Rational secondRational) {
+ long d = gcd(this.denominator, secondRational.denominator);
+ long dd = this.denominator / d * secondRational.denominator;
+ long a = this.numerator * (dd / this.denominator);
+ long b = secondRational.numerator * (dd / secondRational.denominator);
+ return new Rational(a + b, dd);
+ }
+
+ public Rational subtract(Rational secondRational) {
+ long d = gcd(this.denominator, secondRational.denominator);
+ long dd = this.denominator / d * secondRational.denominator;
+ long a = this.numerator * (dd / this.denominator);
+ long b = secondRational.numerator * (dd / secondRational.denominator);
+ return new Rational(a - b, dd);
+ }
+
+ public Rational multiply(Rational secondRational) {
+ return new Rational(this.numerator * secondRational.numerator, this.denominator * secondRational.denominator);
+ }
+
+ public Rational divide(Rational secondRational) {
+ return new Rational(this.numerator * secondRational.denominator, this.denominator * secondRational.numerator);
+ }
+
+ @Override
+ public String toString() {
+ return denominator == 1 ? Long.toString(numerator) : numerator + "/" + denominator;
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/e0302/TestRationalClass.java b/works/life/java-practice/javatest/src/javatest/e0302/TestRationalClass.java new file mode 100644 index 0000000..2be02b9 --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/e0302/TestRationalClass.java @@ -0,0 +1,12 @@ +package javatest.e0302;
+
+public class TestRationalClass {
+ public static void main(String[] args) {
+ Rational r1 = new Rational(2, 1);
+ Rational r2 = new Rational(2, 3);
+ System.out.println(r1 + " + " + r2 + " = " + r1.add(r2));
+ System.out.println(r1 + " - " + r2 + " = " + r1.subtract(r2));
+ System.out.println(r1 + " * " + r2 + " = " + r1.multiply(r2));
+ System.out.println(r1 + " / " + r2 + " = " + r1.divide(r2));
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/e0401/Program.java b/works/life/java-practice/javatest/src/javatest/e0401/Program.java new file mode 100644 index 0000000..c7472b8 --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/e0401/Program.java @@ -0,0 +1,72 @@ +package javatest.e0401;
+
+public class Program {
+ public static boolean equalArea(GeometricObject object1, GeometricObject object2) {
+ return object1.findArea() == object2.findArea();
+ }
+
+ public static void displayGeometricObject(GeometricObject object) {
+ if (object instanceof Circle) {
+ System.out.println("A Circle.");
+ } else if (object instanceof Rectangle) {
+ System.out.println("A Rectangle.");
+ }
+ }
+
+ public static void main(String[] args) {
+ Circle circle = new Circle(3);
+ Rectangle rectangle = new Rectangle(2, 4);
+
+ System.out.println(equalArea(circle, rectangle));
+ displayGeometricObject(circle);
+ displayGeometricObject(rectangle);
+ }
+}
+
+abstract class GeometricObject {
+ protected String color;
+
+ public abstract double findArea();
+
+ public abstract double findPerimeter();
+}
+
+class Circle extends GeometricObject {
+
+ private double radius;
+
+ public Circle(double radius) {
+ this.radius = radius;
+ }
+
+ @Override
+ public double findArea() {
+ return radius * radius * Math.PI;
+ }
+
+ @Override
+ public double findPerimeter() {
+ return radius * 2 * Math.PI;
+ }
+}
+
+class Rectangle extends GeometricObject {
+
+ private double width;
+ private double height;
+
+ public Rectangle(double width, double height) {
+ this.width = width;
+ this.height = height;
+ }
+
+ @Override
+ public double findArea() {
+ return width * height;
+ }
+
+ @Override
+ public double findPerimeter() {
+ return (width + height) * 2;
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/e0402/Person.java b/works/life/java-practice/javatest/src/javatest/e0402/Person.java new file mode 100644 index 0000000..b7e0e14 --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/e0402/Person.java @@ -0,0 +1,40 @@ +package javatest.e0402;
+
+public class Person {
+ public void cut() {
+ }
+
+ public static void main(String[] args) {
+ Person player = new Player();
+ Person cooker = new Cooker();
+ Person cuter = new Cuter();
+
+ player.cut();
+ cooker.cut();
+ cuter.cut();
+ }
+}
+
+/** 演员 */
+class Player extends Person {
+ /** 重写 */
+ public void cut() {
+ System.out.println("停止演戏");
+ }
+}
+
+/** 厨师 */
+class Cooker extends Person {
+ /** 重写 */
+ public void cut() {
+ System.out.println("开始切菜");
+ }
+}
+
+/** 厨师 */
+class Cuter extends Person {
+ /** 重写 */
+ public void cut() {
+ System.out.println("开始剪头发");
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/p0301/AreaAndLength.java b/works/life/java-practice/javatest/src/javatest/p0301/AreaAndLength.java new file mode 100644 index 0000000..5216fb1 --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/p0301/AreaAndLength.java @@ -0,0 +1,120 @@ +package javatest.p0301;
+
+class Trangle {
+ double sideA, sideB, sideC, area, length;
+ boolean boo;
+
+ public Trangle(double a, double b, double c) {
+ sideA = a;
+ sideB = b;
+ sideC = c;// 参数a,b,c分别赋值给sideA,sideB,sideC
+ if (a + b > c && a + c > b && c + b > a) // a,b,c构成三角形的条件表达式
+ {
+ boo = true; // 给boo赋值。
+ } else {
+ boo = false; // 给boo赋值。
+ }
+ }
+
+ double getLength() {
+ if (boo) {
+ length = sideA + sideB + sideC;
+ return length;
+ } else {
+ System.out.println("不是一个三角形,不能计算周长");
+ return 0;
+ }
+ // 方法体，要求计算出length的值并返回
+ }
+
+ public double getArea() {
+ if (boo) {
+ double p = (sideA + sideB + sideC) / 2.0;
+ area = Math.sqrt(p * (p - sideA) * (p - sideB) * (p - sideC));
+ return area;
+ } else {
+ System.out.println("不是一个三角形,不能计算面积");
+ return 0;
+ }
+ }
+
+ public void setABC(double a, double b, double c) {
+ sideA = a;
+ sideB = b;
+ sideC = c; // 参数a,b,c分别赋值给sideA,sideB,sideC
+ if (a + b > c && a + c > b && c + b > a) // a,b,c构成三角形的条件表达式
+ {
+ boo = true; // 给boo赋值。
+ } else {
+ boo = false; // 给boo赋值。
+ }
+ }
+}
+
+class Lader {
+ double above, bottom, height, area;
+
+ Lader(double a, double b, double h) {
+ above = a;
+ bottom = b;
+ height = h;
+ // 方法体，将参数a,b,c分别赋值给above,bottom,height
+ }
+
+ double getArea() {
+ area = (above + bottom) / 2 * height;
+ return area;
+ // 方法体，,要求计算出area返回
+ }
+}
+
+class Circle {
+ double radius, area;
+
+ Circle(double r) {
+ radius = r; // 方法体
+ }
+
+ double getArea() {
+ return 3.14 * radius * radius; // 方法体，要求计算出area返回
+ }
+
+ double getLength() {
+ return 3.14 * 2 * radius; // getArea方法体的代码,要求计算出length返回
+ }
+
+ void setRadius(double newRadius) {
+ radius = newRadius;
+ }
+
+ double getRadius() {
+ return radius;
+ }
+}
+
+public class AreaAndLength {
+ public static void main(String args[]) {
+ double length, area;
+ Circle circle = null;
+ Trangle trangle;
+ Lader lader;
+ circle = new Circle(10); // 创建对象circle
+ trangle = new Trangle(3, 4, 5);// 创建对象trangle。
+ lader = new Lader(3, 4, 10); // 创建对象lader
+ length = circle.getLength(); // circle调用方法返回周长并赋值给length
+ System.out.println("圆的周长:" + length);
+ area = circle.getArea();// circle调用方法返回面积并赋值给area
+ System.out.println("圆的面积:" + area);
+ length = trangle.getLength(); // trangle调用方法返回周长并赋值给length
+ System.out.println("三角形的周长:" + length);
+ area = trangle.getArea(); // trangle调用方法返回面积并赋值给area
+ System.out.println("三角形的面积:" + area);
+ area = lader.getArea(); // lader调用方法返回面积并赋值给area
+ System.out.println("梯形的面积:" + area);
+ trangle.setABC(12, 34, 1); // trangle调用方法设置三个边，要求将三个边修改为12,34,1。
+ area = trangle.getArea(); // trangle调用方法返回面积并赋值给area
+ System.out.println("三角形的面积:" + area);
+ length = trangle.getLength(); // trangle调用方法返回周长并赋值给length
+ System.out.println("三角形的周长:" + length);
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/p0302/Example.java b/works/life/java-practice/javatest/src/javatest/p0302/Example.java new file mode 100644 index 0000000..600a899 --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/p0302/Example.java @@ -0,0 +1,47 @@ +package javatest.p0302;
+
+class A {
+ float a; // 声明一个float型实例变量a
+ static float b; // 声明一个float型类变量b,即static变量b
+
+ void setA(float a) {
+ this.a = a; // 将参数a的值赋值给成员变量a
+ }
+
+ void setB(float b) {
+ this.b = b; // 将参数b的值赋值给成员变量b
+ }
+
+ float getA() {
+ return a;
+ }
+
+ float getB() {
+ return b;
+ }
+
+ void inputA() {
+ System.out.println(a);
+ }
+
+ static void inputB() {
+ System.out.println(b);
+ }
+}
+
+public class Example {
+ public static void main(String args[]) {
+ A.b = 100; // 通过类名操作类变量b,并赋值100
+ A.inputB(); // 通过类名调用方法inputB()
+ A cat = new A();
+ A dog = new A();
+ cat.setA(200); // cat象调用方法setA(int a)将cat的成员a的值设置为200
+ cat.setB(400); // cat调用方法setB(int b)将cat的成员b的值设置为400
+ dog.setA(150); // dog象调用方法setA(int a)将dog的成员a的值设置为150
+ dog.setB(300); // dog调用方法setB(int b)将dog的成员b的值设置为300
+ cat.inputA(); // cat调用inputA()。
+ cat.inputB(); // cat调用inputB()。
+ dog.inputA(); // dog调用inputA()。
+ dog.inputB(); // dog调用inputB()。
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/p0303/SunRise.java b/works/life/java-practice/javatest/src/javatest/p0303/SunRise.java new file mode 100644 index 0000000..dbd964c --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/p0303/SunRise.java @@ -0,0 +1,12 @@ +package javatest.p0303;
+
+import javatest.p0303.sub.*;
+
+class SunRise {
+ public static void main(String args[]) {
+ SquareEquation equation = new SquareEquation(4, 5, 1);
+ equation.getRoots();
+ equation.setCoefficient(-3, 4, 5);
+ equation.getRoots();
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/p0303/sub/SquareEquation.java b/works/life/java-practice/javatest/src/javatest/p0303/sub/SquareEquation.java new file mode 100644 index 0000000..0d7546c --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/p0303/sub/SquareEquation.java @@ -0,0 +1,46 @@ +package javatest.p0303.sub;
+
+public class SquareEquation {
+ double a, b, c;
+ double root1, root2;
+ boolean boo;
+
+ public SquareEquation(double a, double b, double c) {
+ this.a = a;
+ this.b = b;
+ this.c = c;
+ if (a != 0) {
+ boo = true;
+ } else {
+ boo = false;
+ }
+ }
+
+ public void getRoots() {
+ if (boo) {
+ System.out.println("是一元2次方程");
+ double disk = b * b - 4 * a * c;
+ if (disk >= 0) {
+ root1 = (-b + Math.sqrt(disk)) / (2 * a);
+ root2 = (-b - Math.sqrt(disk)) / (2 * a);
+ System.out.printf("方程的根:%f,%f\n", root1, root2);
+ } else {
+ System.out.printf("方程没有实根\n");
+ }
+
+ } else {
+ System.out.println("不是一元2次方程");
+ }
+ }
+
+ public void setCoefficient(double a, double b, double c) {
+ this.a = a;
+ this.b = b;
+ this.c = c;
+ if (a != 0) {
+ boo = true;
+ } else {
+ boo = false;
+ }
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/p0401/Example.java b/works/life/java-practice/javatest/src/javatest/p0401/Example.java new file mode 100644 index 0000000..d673821 --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/p0401/Example.java @@ -0,0 +1,113 @@ +package javatest.p0401;
+
+class People {
+ protected double weight, height;
+
+ public void speakHello() {
+ System.out.println("yayawawa");
+ }
+
+ public void averageHeight() {
+ height = 173;
+ System.out.println("average height:" + height);
+ }
+
+ public void averageWeight() {
+ weight = 70;
+ System.out.println("average weight:" + weight);
+ }
+}
+
+class ChinaPeople extends People {
+ public void speakHello() {
+ System.out.println("你好,吃饭了吗?");
+ }
+
+ // 重写public void speakHello()方法，要求输出类似“你好，吃了吗”这样的
+ // 汉语信息
+ public void averageHeight() {
+ height = 173;
+ System.out.println("中国人的平均身高：" + height + "厘米");
+ }
+
+ // 重写public void averageHeight()方法，要求输出类似
+ // “中国人的平均身高：168.78厘米”这样的汉语信息
+ public void averageWeight() {
+ weight = 67.34;
+ System.out.println("中国人的平均体重：" + weight + "公斤");
+ }
+
+ // 重写public void averageWeight()方法，
+ // 要求输出类似“中国人的平均体重：65公斤”这样的汉语信息
+ public void chinaGongfu() {
+ System.out.println("坐如钟,站如松,睡如弓");// 输出中国武术的信息，例如："坐如钟,站如松,睡如弓"等
+ }
+}
+
+class AmericanPeople extends People {
+ public void speakHello() {
+ System.out.println("How do You do");
+ }
+
+ // 重写public void speakHello()方法，要求输出类似
+ // “How do you do”这样的英语信息。
+ public void averageHeight() {
+ height = 188;
+ System.out.println("Amerian Average height:" + height + " cm");
+ }
+
+ // 重写public void averageHeight()方法
+ public void averageWeight() {
+ weight = 80.23;
+ System.out.println("Amerian Average weight:" + weight + " kg");
+ }
+
+ // 重写public void averageWeight()方法
+ public void americanBoxing() {
+ System.out.println("直拳、钩拳");// 输出拳击的信息，例如，“直拳”、“钩拳”等
+ }
+}
+
+class BeijingPeople extends ChinaPeople {
+ public void speakHello() {
+ System.out.println("您好");
+ }
+
+ // 重写public void speakHello()方法，要求输出类似“您好”这样的汉语信息
+ public void averageHeight() {
+ height = 16;
+ System.out.println("北京人的平均身高：" + height + "厘米");
+ }
+
+ // 重写public void averageHeight()方法
+ public void averageWeight() {
+ weight = 6;
+ System.out.println("北京人的平均体重：" + weight + "公斤");
+ }
+
+ // 重写public void averageWeight()方法
+ public void beijingOpera() {
+ System.out.println("京剧术语");// 输出京剧的信息
+ }
+}
+
+public class Example {
+ public static void main(String args[]) {
+ ChinaPeople chinaPeople = new ChinaPeople();
+ AmericanPeople americanPeople = new AmericanPeople();
+ BeijingPeople beijingPeople = new BeijingPeople();
+ chinaPeople.speakHello();
+ americanPeople.speakHello();
+ beijingPeople.speakHello();
+ chinaPeople.averageHeight();
+ americanPeople.averageHeight();
+ beijingPeople.averageHeight();
+ chinaPeople.averageWeight();
+ americanPeople.averageWeight();
+ beijingPeople.averageWeight();
+ chinaPeople.chinaGongfu();
+ americanPeople.americanBoxing();
+ beijingPeople.beijingOpera();
+ beijingPeople.chinaGongfu();
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/p0402/Subroutine.java b/works/life/java-practice/javatest/src/javatest/p0402/Subroutine.java new file mode 100644 index 0000000..6b11ace --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/p0402/Subroutine.java @@ -0,0 +1,23 @@ +package javatest.p0402;
+
+class Parent { // 父类
+ Parent() {
+ System.out.println("调用父类的parent()构造方法");
+ }
+}
+
+class SubParent extends Parent { // 继承Parent类
+ SubParent() {
+ System.out.println("调用子类的SubParent()构造方法");
+ }
+}
+
+public class Subroutine extends SubParent { // 继承SubParent类
+ Subroutine() {
+ System.out.println("调用子类的Subroutine()构造方法");
+ }
+
+ public static void main(String[] args) {
+ Subroutine s = new Subroutine(); // 实例化子类对象
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/p0403/Parallelogram.java b/works/life/java-practice/javatest/src/javatest/p0403/Parallelogram.java new file mode 100644 index 0000000..329aa80 --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/p0403/Parallelogram.java @@ -0,0 +1,31 @@ +package javatest.p0403;
+
+class Quadrangle {
+ public static void draw(Quadrangle q) {
+ // SomeSentence
+ }
+}
+
+class Square extends Quadrangle {
+ // SomeSentence
+}
+
+class Anything {
+ // SomeSentence
+}
+
+public class Parallelogram extends Quadrangle {
+ public static void main(String args[]) {
+ Quadrangle q = new Quadrangle(); // 实例化父类对象
+ // 判断父类对象是否为Parallelogram子类的一个实例
+ if (q instanceof Parallelogram) {
+ Parallelogram p = (Parallelogram) q; // 向下转型操作
+ }
+ // 判断父类对象是否为Parallelogram子类的一个实例
+ if (q instanceof Square) {
+ Square s = (Square) q; // 进行向下转型操作
+ }
+ // 由于q对象不为Anything类的对象，所以这条语句是错误的
+ // System.out.println(q instanceof Anything);
+ }
+}
diff --git a/works/life/java-practice/javatest/src/javatest/p0404/Quadrangle.java b/works/life/java-practice/javatest/src/javatest/p0404/Quadrangle.java new file mode 100644 index 0000000..c6b6630 --- /dev/null +++ b/works/life/java-practice/javatest/src/javatest/p0404/Quadrangle.java @@ -0,0 +1,36 @@ +package javatest.p0404;
+
+public class Quadrangle {
+ // 实例化保存四边形对象的数组对象
+ private Quadrangle[] qtest = new Quadrangle[6];
+ private int nextIndex = 0;
+
+ public void draw(Quadrangle q) { // 定义draw()方法，参数为四边形对象
+ if (nextIndex < qtest.length) {
+ qtest[nextIndex] = q;
+ System.out.println(nextIndex);
+ nextIndex++;
+ }
+ }
+
+ public static void main(String[] args) {
+ // 实例化两个四边形对象，用于调用draw()方法
+ Quadrangle q = new Quadrangle();
+ q.draw(new Square()); // 以正方形对象为参数调用draw()方法
+ // 以平行四边形对象为参数调用draw()方法
+ q.draw(new Parallelogramgle());
+ }
+}
+
+class Square extends Quadrangle { // 定义一个正方形类，继承四边形类
+ public Square() {
+ System.out.println("正方形");
+ }
+}
+
+// 定义一个平行四边形类，继承四边形类
+class Parallelogramgle extends Quadrangle {
+ public Parallelogramgle() {
+ System.out.println("平行四边形");
+ }
+}
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