JS Getting Started instance the definition and invocation of the constructor \ Method \ Prototype Object

Source: Internet
Author: User
Tags define object definition functions variables string square root variable
js| Objects | functions

<script language= "JavaScript" >
function Circel (RADIUS)
{//This function defines the class itself, and the following R is an instance variable defined and initialized by the constructor
This.r=radius;
}
The property is a class variable, and he belongs to a property of the constructor
Circel. pi=3.14159;
function Area ()
{//This is certainly the formula for calculating the circle area.
return this. PI * THIS.R * THIS.R;
}
Here we make it an instance method by assigning the function to the circular object of the constructor.
To be compatible with NAVIGATOR3, we must create and discard an object before the prototype object is generated
New Circel (0);
Circel.prototype.area=area;
Here's another function that compares the two parameters and returns the larger one
function Circel_max (a,b)
{
if (A.R > B.R)
return A;
Else
return b;
}
Because the function compares two objects, it makes no sense to consider him as a single Circel instance method operation.
But we do not want to be a separate function, so we assign him to a constructor so that he becomes a class method
Circel.max=circel_max;
The following code uses the various fields of Circel
var c=new circel (1.0); Create an instance of the Circel class
c.r=2.2; Set a variable for an instance R
var a=c.area (); Call the area method of an instance
var x=math.exp (Circel.    PI); Using variable pi in our own calculations
var d=new circel (1.2); Create another Circel instance
var Bigger=circel.max (c,d);//Use class method Circel.max
</script>
Jscript.js file
/**//* JScript Files
The plural is the sum of an imaginary number and an imaginary number, and the imaginary I is the square root of 1.
*/

/**//* The first step in defining a class is to define the constructor of the class, and the eligibility constructor initializes all instance functions of the object
These properties are the core "state variables" that make each instance of the class distinct
*/

function JScript (real,img)
{
this.x=real;//real number of parts
this.y=img;//Virtual Number part
}

/**//* the second step in defining a function is to define his instance method (or other properties) in the stereotype object of the constructor.
Any attribute defined by the object will be inherited by all instances of this class
Note that the instance method implicitly operates on the This keyword, and many methods do not require additional parameters
*/

//Returns the size of the complex number, which is defined as the distance from the origin (0,0) to the complex plane
Jscript.prototype.magnitude=function ()
{
    return MATH.SQRT (this.x * this.x + this.y * this.y);
};
//Returns the opposite number of the plural
jscript.prototype.negative=function ()
{
    return new JScript (-this.x,- THIS.Y);
};
//To replace a JScript object with a string in an efficient manner, which would be a function called when using a JScript object as a string
Jscript.prototype.tostring=function ()
{
    return "{" + this.x + "," + This.y + "}";
};
//Returns the real part of a complex number that is invoked when a JScript object is processed as a raw value
Jscript.prototype.valueof=function () {return this.x;}

The third step of the/**//* definition class is to define the class method.
Constants and other class variables as functions to construct their own properties (rather than the properties of the stereotype objects of constructors)
Note static methods, which do not use the This keyword, because they operate on only the parameters
*/
Calculates and returns the results of two complex numbers
Jscript.add () =function (a,b)
{
return new JScript (a.x + b.x, A.Y + b.y);
};
Reduce another complex number with a complex number and return the result
Jscript.subtract () =function (a,b)
{
return new JScript (a.x-b.x, A.Y-B.Y);
};
Calculates the product of two complex numbers and returns the result
Jscript.multiply () =function (a,b)
{
return new JScript (a.x * b.x-a.y * b.y, a.x * b.x + x.y * b.y);
};

/**//* below are some useful predefined complex numbers that are defined as class variables so that they can be used as constants (note that they are not actually read-only)
*/

Jscript.zero=new JScript (0,0);
Jscript.one=new JScript (1.0);
Jscript.i=new JScript (0.1);



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