福建工程学院国脉信息学院《JAVa有理数的类封装》

实验1 有理数的类封装模板代码Rational.javaclass Rational {int numerator,denominator;Rational(){}Rational(int a,int b){setNumeratorAndDenominator(a,b);}void setNumeratorAndDenominator(int a,int b){ //设置分子和分母int c=f(Math.abs(a),Math.abs(b)); //计算最大公约数numerator=a/c;denominator=b/c;if(numerator<0&&denominator<0){numerator=-numerator;denominator=-denominator;}}int getNumerator() {return numerator;}int getDenominator() {return denominator;}int f(int a,int b){ //求a和b的最大公约数if(a<b){int c=a;a=b;b=c;}int r=a%b;while(r!=0){a=b;b=r;r=a%b;}return b;}Rational add(Rational r) {int a=r.getNumerator();int b=r.getDenominator();int newNumerator=numerator*b+denominator*a;int newDenominator=denominator*b;Rational result=new Rational(newNumerator,newDenominator);return result;}Rational sub(Rational r) {int a=r.getNumerator();int b=r.getDenominator();int newNumerator=numerator*b-denominator*a;int newDenominator=denominator*b;Rational result=new Rational(newNumerator,newDenominator);return result;}Rational muti(Rational r) {int a=r.getNumerator();int b=r.getDenominator();int newNumerator=numerator*a;int newDenominator=denominator*b;Rational result=new Rational(newNumerator,newDenominator);return result;}Rational div(Rational r) {int a=r.getNumerator();int b=r.getDenominator();int newNumerator=numerator*b;int newDenominator=denominator*a;Rational result=new Rational(newNumerator,newDenominator);return result;}}Computer.javapublic class Computer {public static void main(String args[]) {Rational r1;r1 = new Rational(1,5);//创建分子、分母分别为1和5的有理数Rational r2;r2= new Rational(3,2);//创建分子、分母分别为3和2的有理数Rational result= r1.add(r2); //r1调用方法和r2做加法运算int a= result.getNumerator(); // result调用方法返回自己的分子int b= result.getDenominator(); // result调用方法返回自己的分母double p=a;double q=b;double doubleResult=p/q;System.out.print("分数"+r1.getNumerator()+"/"+r1.getDenominator());System.out.print("与分数"+r2.getNumerator()+"/"+r2.getDenominator()+"的和等于");System.out.println(a+"/"+b+"="+doubleResult);r1.setNumeratorAndDenominator(4,7);r2.setNumeratorAndDenominator(-5,20);result=r1.muti(r2);a=result.getNumerator();b=result.getDenominator();p=a;q=b;doubleResult=p/q;System.out.print("分数"+r1.getNumerator()+"/"+r1.getDenominator());System.out.print("与分数"+r2.getNumerator()+"/"+r2.getDenominator()+"的积等于");System.out.println(a+"/"+b+"="+doubleResult);}}实验2 实例成员与类成员模板代码Exm_1.javaclass A {float a; //声明一个实例float变量astatic float b; //声明一个static的float变量bvoid 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 Exm_1 {public static void main(String args[ ]) {A b=new A();b.setB(100); // 通过类名操作类变量b，并赋值100A.inputB(); // 通过类名调用方法inputB( )A cat=new A( );A dog=new A( );cat.setA(200); // cat调用方法setA(int a)将cat的成员a的值设置为200cat.setB(400); // cat调用方法setB(int b)将cat的成员b的值设置为400dog.setA(200); // dog调用方法setA(int a)将dog的成员a的值设置为200dog.setB(900); // dog调用方法setB(int b)将dog的成员b的值设置为900cat.inputA(); // cat调用inputA( )cat.inputB(); // cat调用inputB( )dog.inputA(); // dog调用inputA( )dog.inputB(); // dog调用inputB( )}}Exm_2.javaclass Point {public double x;public double y;public double getX() {return this.x;}public void setX(double x) {this.x = x;}public double getY() {return this.y;}public void setY(double y) {this.y = y;}public Point(double x, double y) {this.x=x;this.y=y;}}class Circle{double x;//圆心横坐标double y;//圆心纵坐标double r;//圆半径final double PI = 3.1415926;public Circle(Point p,double r){this.x = p.x;this.y = p.y;this.r = r;}public void setXY(Point p){this.x = p.x;this.y = p.y;}public void setR(double r){this.r = r;}public double getArea(){return this.PI *this.r*this.r;}public void getResult(Point p)//添加一个方法，计算一个点（Point对象）是否在圆（Cricle 对象）内{double distance = (this.x-p.x)*(this.x-p.x)+(this.y-p.y)*(this.y-p.y); //点到圆心的距离的平方if(distance -r*r<= 0)System.out.println("点在圆内");elseSystem.out.println("点不在圆内");}}public class Exm_2{public static void main(String[] args){Point point = new Point(2,3);Point p = new Point(10,8);Circle circle = new Circle(point,5);circle.getResult(p);//输出结果}}。