87 lines
1.9 KiB
JavaScript
87 lines
1.9 KiB
JavaScript
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/*
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* Énoncé:
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* Étant donné les classes Shape & Point définies ci dessous, implémenter les sous classes de Shape
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* Circle et Square et leur méthode getPerimeter respective.
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*/
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/* Shape */
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function Shape() {}
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Shape.prototype.getPerimeter = function() {
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throw new Error('La méthode getPerimeter doit être implémentée par les sous classes !');
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};
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/* Point */
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function Point(x, y) {
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this.x = x;
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this.y = y;
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}
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Point.prototype.getDistanceFrom = function(point) {
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if( !(point instanceof Point) ) {
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throw new Error('L\'argument "point" doit être une instance de Point !');
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}
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return Math.sqrt( (this.x-point.x)*(this.x-point.x) + (this.y-point.y)*(this.y-point.y));
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};
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/* Square */
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function Polygon(p1, p2, p3, p4) {
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this._points = Array.prototype.slice.call(arguments); // Arguments to array
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}
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Polygon.prototype = Object.create(Shape.prototype);
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Polygon.prototype.getPerimeter = function() {
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var points = this._points;
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return points.reduce(function(perimeter, point, i) {
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return perimeter + point.getDistanceFrom(points[(i+1)%points.length]);
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}, 0);
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};
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/* Circle */
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function Circle(center, radius) {
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this.center = center;
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this.radius = radius;
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}
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Circle.prototype = Object.create(Shape.prototype);
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Circle.prototype.getPerimeter = function() {
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return Math.PI * 2 * this.radius;
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};
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/* Tests */
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var p1 = new Point(1, 5);
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var p2 = new Point(2, 6);
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var p3 = new Point(2, -10);
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var p4 = new Point(7, -2);
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try {
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var poly = new Polygon(p1, p2, p3, p4);
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console.log( poly instanceof Polygon ); // -> true
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console.log( poly instanceof Shape ); // -> true
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console.log( poly.getPerimeter() ); // -> 36.06773915172259
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} catch(err) {
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console.error(err);
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}
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var c = new Circle(p1, 5);
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try {
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console.log( c instanceof Circle ); // -> true
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console.log( c instanceof Shape ); // -> true
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console.log( c.getPerimeter() ); // -> 31.41592653589793
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} catch(err) {
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console.error(err);
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}
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