Code Year 2012 - Week 3

3週目。復習が多くていまいち物足りない。
switchで文字列が使えるのはJavaと違って便利よいね。
3項演算子も使い慣れると便利。これはJavaにもある。

	// 1. More on the "if" statement
	var yourName = "";
	var result = "";
	if (0 === yourName.length) {
	result = "What is your name?";
	}
	// 2. Matching a condition or doing something else
	var yourName = "";
	var result = "";
	// use the > symbol to check the length of yourName
	if (0 < yourName.length) {
	result = "Hi "+ yourName;
	} else {
	result = "What is your name?";
	}
	// 3. Testing one or more conditions
	var yourName = "Hanako";
	var gender = "female";
	var result;
	if ("male" === gender) {
	result = "His name is "+yourName;
	} else if ("female" === gender) {
	result = "Her name is "+yourName;
	} else {
	result = "Hi "+yourName;
	}
	// 4. Checking a condition for at least one result
	var yourName = "Taro";
	var gender = "male";
	// don't forget to use the || operator
	if ( "male" === gender || "female" === gender ) {
	result = true;
	} else {
	result = false;
	}
	// 5. Checking for two conditions
	var yourName = "Taro";
	var gender = "male";
	var result;
	if (0 < yourName.length && 0 < gender.length) {
	result = "Thanks";
	} else {
	result = "Please make sure both yourName and gender are filled in.";
	}
	// 6. Nesting conditional statements
	var yourName = "Taro";
	var gender = "male";
	var result;
	//Line 10 starts an if statement
	//Nested in this if statement is an if else statement on lines 11 - 15
	//This nested if else statement allows us to check another condition
	//We close the first if statement at the start of line 16
	if (0 < yourName.length && 0 < gender.length) {
	if ("male" === gender || "female" === gender) {
	result = "Thanks";
	} else {
	result = "Please enter male or female for gender.";
	}
	} else {
	result = "Please tell us both your name and gender.";
	}

view raw 2.js hosted with ❤ by GitHub

	// 1. Using if else statements in functions
	var checkNameGender = function (yourName,gender) {
	//All the code below was used in exercise 1.6
	if (gender.length > 0 && yourName.length > 0) {
	if (gender === 'male' || gender === 'female') {
	return true;
	} else {
	return false;
	}
	} else {
	return false;
	}
	};
	checkNameGender("Taro", "male");
	// 2. Using if else statements within functions
	var legalDrivingAge = 18;
	var canIDrive =
	// write if else statement here. Return true or false
	function(myAge){
	return legalDrivingAge <= myAge;
	};
	canIDrive(29);
	// 3. Functions in if else statements
	// Define the function under this line
	var canIDrive = function(myAge, legalDrivingAge){
	return legalDrivingAge <= myAge;
	};
	// Declare legalDrivingAge under myAge
	var myAge = prompt("How old are you?");
	var legalDrivingAge = 18;
	//Create an if else statement using the function as a condition
	if (canIDrive(myAge, legalDrivingAge)) {
	console.log("You can legally drive!");
	}
	else {
	console.log("You'll have to wait a few more years!");
	}

view raw 3.js hosted with ❤ by GitHub

	// 1. Background to switch statements
	var jacketColor = "green";
	var result;
	switch (jacketColor) {
	case "black":
	result = "Pay $300";
	break;
	case "brown":
	result = "Pay $200";
	break;
	case "green":
	result = "Pay $5";
	break;
	default:
	result = "This color does not match my eyes!";
	}
	// 2. Introducing the switch statement
	var myCar = "Toyota";
	var result;
	switch (myCar) {
	case "Ford":
	result = "American brand";
	break;
	case "Toyota":
	result = "Japanese brand";
	break;
	default:
	result = "I'm not sure what country that car is from";
	break;
	}
	// 3. Write your own switch statement
	var born = prompt("What country were you born in?");
	var result;
	switch (born) {
	case "USA":
	result = "Born in the USA";
	break;
	default:
	result = "Born outside the USA";
	break;
	}
	// 4. Switch it up
	var born = prompt("What country were you born in?");
	var result;
	// write the whole switch statement
	switch(born) {
	case "USA":
	result = 1;
	break;
	case "England":
	result = 2;
	break;
	default:
	result = 3;
	break;
	}

view raw 4.js hosted with ❤ by GitHub

	// 1. Introducing the shortcut
	var x = 2;
	var y = 1;
	if (x > y) {
	result = "good job";
	}
	else {
	result = 20;
	}
	//Below is the above code written using the ternary operator
	result = x > y ? "good job" : 20;
	// 2. Practice
	var myAge = 29;
	// a simple if else statement
	if (myAge >= 18) {
	answer = "adult";
	}
	else {
	answer = "non-adult" ;
	}
	// rewrite the code above using a ternary operator
	answer = 18 <= myAge ? "adult": "non-adult";
	// 3. More practice!
	//Original if else statement
	//Rewrite the above code using the ternary operator
	result = "Nick" === name ? true: false;
	// 4. Setting values using a ternary operators
	var food = prompt("What food do you like ?");
	var foodType;
	if (food === "taco") {
	foodType = "Mexican";
	} else {
	foodType = "other";
	}
	//Re-write the above code using a ternary operator
	foodType = "taco" === food ? "Mexican": "other";

view raw 5.js hosted with ❤ by GitHub

	// 1. Conditionals
	var gender = "female";
	if (gender === "female") {
	result = "true";
	}
	else {
	result = "false";
	}
	// 2. Nested Conditionals: Part 1
	var gender = "female";
	if (gender === "female") {
	result = "true";
	}
	else {
	result = "false";
	}
	// 3. Nested Conditionals: Part 2
	var topThree = "true";
	var winner = "false";
	var result;
	if (topThree === "false") {
	result = "Sorry, empty handed";
	}
	else {
	if (winner === "true") {
	result = "Gold!!!";
	} else {
	result = "Not bad! Got a medal!";
	}
	}
	// 4. Switch Statements
	var jacketColor = "black";
	var result;
	switch (jacketColor) {
	case "black":
	result = "Pay $300";
	break;
	case "brown":
	result = "Pay $200";
	break;
	case "green":
	result = "Pay $5";
	break;
	default:
	result = "This color does not match my eyes!";
	}
	// 5. Ternary operator
	var x = 10;
	var y = 20;
	//Rewrite the ternary code using if else statements
	if(x > y) {
	result = "good job";
	} else {
	result = 20;
	}

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