How should you build the code segment?

HOTSPOT

You are creating a function by using JavaScript. The function accepts an object as the parameter and returns a string that identifies the data type of the object.

You have the following requirements:

• The function must return "Number" if the object is a number.

• The function must return "String" if the object is a string.

• The function must return "Unknown" if the object is neither a number nor a string.You need to implement the function to meet the requirements.

How should you build the code segment? (To answer, select the appropriate options from the drop-down lists in the answer area.)

View Answer

Answer:

Explanation:

* Use the switch statement to select one of many blocks of code to be executed.

Syntax

switch(expression) {

case n:

code block

break;

case n:

code block

break;

default:

default code block

}

This is how it works:

The switch expression is evaluated once.

The value of the expression is compared with the values of each case.

If there is a match, the associated block of code is executed.

* Object.prototype.constructor

Returns a reference to the Object function that created the instance’s prototype. Note that the value of this property is a reference to the function itself, not a string containing the function’s name. The value is only read-only for primitive values such as 1, true and "test".

* Description

All objects inherit a constructor property from their prototype:

var o = {};

o.constructor === Object; // true

var a = [];

a.constructor === Array; // true

var n = new Number(3);

n.constructor === Number; // true

* The constructor property is created together with the function as a single property of func.prototype.

Reference: JavaScript Switch Statement;Object.prototype.constructor