Code Year 2012 - Week 2

Code Year 2012の２週目。関数のお勉強。
２週目は３つコースが用意されている。とりあえず一つ目をこなした。

	// 1. Introduction
	var hello = function () {
	// Print hello on the console.
	console.log("i am saying hello");
	};
	hello();
	hello();
	// 2. Function
	var hi = function () {
	console.log("hi");
	};
	hi();
	// 3. My first function
	var myFirstFunction = function() {
	console.log('Manabu');
	};
	myFirstFunction();
	// 4. Fix me !
	var fullName = "";
	var name;
	var firstLetter;
	/*
	fixName function definition should go here.
	*/
	var fixName = function(){
	firstLetter = name.substring(0, 1);
	name = firstLetter.toUpperCase() + name.substring(1);
	fullName = fullName + " " + name;
	};
	name = prompt("Enter your first name (all in lower case):");
	fixName();
	name = prompt("Enter your second name (all in lower case):");
	fixName();
	console.log("And your full name is:" + fullName);

view raw 1.js hosted with ❤ by GitHub

	// 1. Ahoy matey!
	var greeting = "Ahoy";
	// 2. Thou shalt greet
	var greeting = "Ahoy";
	var greet = function() {
	console.log(greeting);
	};
	greet();
	// 3. Domesticate
	var greeting = "Ahoy";
	var greet = function () {
	// Local greeting variable.
	var greeting = "Hello";
	console.log(greeting);
	};
	greet();
	// 4. Sometimes change is bad
	var greeting = "Ahoy";
	var greet = function () {
	// Local greeting variable.
	var greeting = "Hello";
	console.log(greeting);
	};
	greet();
	console.log(greeting);
	// 5. Parameters
	var sayHelloTo = function (name) {
	console.log("Hello " + name);
	};
	sayHelloTo("Amjad");
	sayHelloTo("Manabu");
	// 6. Recap
	/* Start global variable `greeting` scope */
	var greeting = "Ahoy";
	var greet = function () {
	/* Start local variable `greeting` scope */
	var greeting = "Hello";
	/* Start local variable `myName` scope */
	var myName = prompt("Input your name: ");
	console.log(greeting + " " + myName);
	/* End local variables `myName` and `greeting` scope */
	};
	greet();
	// This will produce a `ReferenceError` since we are out
	// of the `myName` variable scope.
	console.log(myName);

view raw 2.js hosted with ❤ by GitHub

	// 1. Introduction
	var identity = function (x) {
	return x;
	};
	identity(999);
	// 2. Square
	var square = function (x) {
	return x * x;
	};
	// 3. More on return
	var identity = function (x) {
	return x;
	};
	// 4. Branch and return
	var isEven = function (n) {
	if (n % 2 === 0) {
	return true;
	} else {
	return false;
	}
	};
	console.log(isEven(1));
	console.log(isEven(2));
	console.log(isEven(999));
	// 5. The lost numbers
	var lost = [4, 8, 15, 16, 23, 42];
	var count = lost.length;
	var isLost = function (n) {
	for ( var i = 0; i < count; i++ ) {
	if ( n === lost[i]) {
	return true;
	}
	}
	return false;
	};
	if ( isLost(12) ) {
	console.log('12 is a lost number');
	}
	if ( isLost(16) ) {
	console.log('16 is a lost number');
	}

view raw 3.js hosted with ❤ by GitHub

	// 1. Function calls as values
	// Define quarter here.
	var quarter = function( x ) {
	return x / 4;
	};
	if (quarter(4) === 1) {
	console.log("The statement is true.");
	} else {
	console.log("The statement is false.");
	}
	// 2. Cube
	var cube = function( n ) {
	return n * n * n;
	};
	// 3. Squares n'cubes
	var square = function (x) {
	return x * x;
	};
	var cube = function (x) {
	return square(x) * x;
	};
	// 4. What not
	var isMultipleOfThree = function (x) {
	return x % 3 === 0;
	};
	var isNotMultipleOfThree = function (x) {
	return !isMultipleOfThree(x);
	};
	// 5. Even is not odd
	var isOdd = function( x ) {
	return x % 2 != 0;
	};
	var isEven = function( x ) {
	return !isOdd(x);
	};

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	// 1. Let there be more
	var area = function (w, l) {
	// We should return the product of w and l.
	return w * l;
	};
	// 2. Divisibility
	var isDivisible = function (x, y) {
	return x % y === 0;
	};
	// 3. Power
	var power = function (base, exponent) {
	var result = 1;
	for (var i = 0; i < exponent; i++) {
	result = result * base;
	}
	return result;
	};
	power(2, 2);
	// 4. Recursive: Part 1
	var power = function( base, exponent ){
	};
	// 5. Recursive: Part 2
	var power = function( base, exponent ){
	if(0 === exponent) {
	return 1;
	}
	};
	// 6. Recursive: Part 3
	var power = function( base, exponent ){
	if(0 === exponent) {
	return 1;
	}
	return base * power(base, exponent -1);
	};
	// 7. Recursive: Part 4
	var power = function( base, exponent ){
	if(0 === exponent) {
	return 1;
	}
	return base * power(base, exponent -1);
	};
	console.log(power(2, 4) === 16);
	console.log(power(2, 0) === 1);
	console.log(power(3, 3) === 27);

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