JS中类和对象的学习之七道习题实现【分别定义一个猫，狗，枪，匕首，矩形（有求面积，求周长的方法），圆（有求面积，求周长的方法），分数（有求和，求差，求乘积，除，约分的方法）类】

定义一个手机对象——
手机包含两个属性：品牌，价格；
手机包含两个方法：打电话，发短信；

<script type="text/javascript">

	var phone = {
		brand : "vivo",
		price : 1999,
		call : function(){
			document.write(this.brand + "拨号中" + "<br>");
		},
		message: function(context){
			document.write("正在发短信:" + context + "<br>");
		},
	}
	// 调用对象属性
	document.write(phone.brand + "<br>");
	// 为对象添加属性
	phone.ap = "100血";
	document.write(phone.ap + "<br>");
	
	// 调用对象方法   没有参数
	phone.call();
	// 调用对象方法   有参数
	phone.message("你好！");
	
</script>

定义一个“人”类——
具有三个属性：name,age,sex；
两个方法：eat()和sleep()方法；

<script type="text/javascript">
	function Person(name,age,sex){
		this.name = name;
		this.age = age;
		this.sex = sex;
		this.eat = function(food){
			document.write(this.name + "正在吃" + food + "<br>");
		};
		this.sleep = function(){
			document.write(this.name + "正在睡觉！" + "<br>");
		};
		
	}
	
	// 通过类创建一个p1对象格式：var 对象 = new 类名(参数);
	var p1 = new Person("张三", 28, "男");
	
	// 调用对象属性
	document.write(p1.name + "<br>");
	// 调用对象方法   没参数
	p1.sleep();
	// 调用对象方法   有参数
	p1.eat("香蕉！" + "<br>");
</script>

<script type="text/javascript">
		
	// 第一题:定义一个猫（Cat）类，猫有name和age属性，有一个catchMouse方法
	function Cat(name, age){
		this.name = name;
		this.age = age;
		this.catchMouse = function(){
			console.log("抓老鼠ing!");
		};
	}
	var cat = new Cat("汤姆",21);
	console.log(cat.name + "-" + cat.age);
	cat.catchMouse();
	
	
	// 第二题：定义一个狗（Dog）类，狗有name和age属性，有一个lookDoor方法
	function Dog(name,age){
		this.name = name;
		this.age = age;
		this.lookDoor = function(){
			console.log("看门ind!");
		};
	}
	var dog = new Dog("Peter", 22);
	console.log(dog.name);
	console.log(dog.age);
	dog.lookDoor();
	
	// 第三题：定义一个枪（Gun）类，枪有name,ap和price属性，有一个发射子弹的方法fire
	// 和一个更换弹夹的方法reload
	function Gun(name,ap,price){
		this.name = name;
		this.ap = ap;
		this.price = price;
		this.fire = function(){
			console.log(this.name + "正在开枪！");
		};
		this.reload = function(){
			console.log(this.name + "正在换弹夹！");
		};
	};
	var gun = new Gun("冲锋枪", "100血", 9999);
	console.log(gun.name);
	console.log(gun.ap);
	console.log(gun.price);
	gun.fire();
	gun.reload();
	
	// 第四题:定义一个匕首（Dagger）类，匕首有name,ap和price属性，有***方法attack
	function Dagger(name,ap,price){
		this.name = name;
		this.ap = ap;
		this.price = price;
		this.attack = function(){
			console.log("正在***！");
		};
	};
	var dagger = new Dagger("尼泊尔", "100血", 19999);
	console.log(dagger.name);
	console.log(dagger.ap);
	console.log(dagger.price);
	dagger.attack();
	
	// 第五题：定义一个矩形（Rectangle）类，矩形有x,y,width,height属性，有计算周长
	// 的方法perimeter，有计算面积的方法area
	function Rectangle(x,y,width,height){
		this.x = x;
		this.y = y;
		this.width = width;
		this.height = height;
		this.perimeter = function(){
			var num = this.width * 2 + this.height * 2;
			console.log("周长是" + num);
		};
		this.area = function(){
			var area = this.width * this.height;
			console.log("面积是：" + area);
		};
	};
	var rectangle = new Rectangle(0,0,10,5);
	console.log(rectangle.x);
	console.log(rectangle.y);
	console.log(rectangle.width);
	console.log(rectangle.height);
	rectangle.perimeter();
	rectangle.area();

	// 第六题：定义一个圆（Circle)类，圆有x,y,r属性，有计算周长的方法perimeter,
	// 有计算面积的方法area
	function Circle(x,y,r){
		this.x = x;
		this.y = y;
		this.r = r;
		this.perimeter = function(){
			var num = Math.PI * 2 * r;
			num = Math.round(num);
			console.log("周长是：" + num);
		};
		this.area = function(){
			var area = 1/2 * Math.PI * r * r;
			area = Math.round(area);
			console.log("面积是：" + area);
		}
	};
	var circle = new Circle(0,0,5);
	console.log(circle.x);
	console.log(circle.y);
	console.log(circle.r);
	circle.perimeter();
	circle.area();
	
	// 第七题：定义一个分数（Fraction）类，分数类有分子numerator，分母denominator属性
	// 有求和，求差，求乘积，除，约分的方法
			function Fraction(numerator,denominator){
		this.numerator = numerator;
		this.denominator = denominator;
		this.print = function(){
			console.log(this.numerator + "/" + this.denominator);
		};
		this.add = function(fs1){
			var fz = this.numerator*fs1.denominator + fs1.numerator*this.denominator;
			var fm = this.denominator*fs1.denominator;
			var result = new Fraction(fz,fm);
			return result;
		};
		this.minus = function(fs1){
			var fz = this.numerator*fs1.denominator - fs1.numerator*this.denominator;
			var fm = this.denominator*fs1.denominator;
			var result = new Fraction(fz,fm);
			return result;
		};
		this.product = function(fs1){
			var fz = this.numerator*fs1.numerator;
			var fm = this.denominator*fs1.denominator;
			var result = new Fraction(fz,fm);
			return result;
		};
		this.divide = function(fs1){
			var fz = this.numerator*fs1.denominator;
			var fm = this.denominator*fs1.numerator;
			var result = new Fraction(fz,fm);
			return result;
		};
		// 辗转相除法求分数最大公约数
		this.reduce = function(){
			var fz = this.numerator;
			var fm = this.denominator;
			
			// 辗转相除法
			while(fz % fm != 0){  // 只要分子对分母求余数，余数不等于0，进入循环
				var yushu = fz % fm;
				fz = fm;
				fm = yushu;
			};
			// 循环结束后，fm就是最大公约数
			this.numerator /= fm;
			this.denominator /= fm;
		};
		
	}
	
	var fraction1 = new Fraction(40,60);
	fraction1.print();
	
	var fraction2 = new Fraction(2,6);
	fraction2.print();
	
	// 两个分数求和
	var fraction3 = fraction1.add(fraction2);
	fraction3.print();
	// 两个分数求差
	var fraction3 = fraction1.minus(fraction2);
	fraction3.print();
	// 两个分数求乘积
	var fraction3 = fraction1.product(fraction2);
	fraction3.print();
	// 两个分数求除
	var fraction3 = fraction1.divide(fraction2);
	fraction3.print();
	// 分数约分
	fraction1.reduce();
	fraction1.print();
</script>

标签：function,console,周长,求差,denominator,log,var,方法,name
来源： https://blog.51cto.com/u_15264787/2886753