panpsychism/unit_03/w08d02/homework

CAESAR CIPHER

Angular js basics

APP

Make a Caesar Cipher page that takes an input and encodes it with a Caesar Cipher and and displays the encoded input while the user is typing. (no submit button).

Also make it so the user can decode an encoded message.

ANGULAR DIRECTIVES

• ng-keyup
• ng-model

CAESAR CIPHER

https://en.wikipedia.org/wiki/Caesar_cipher

You can put this Caesar Cipher code in a separate js file (before your main app.js), and then reference the caesarShift function in your angular controller.

In the example in the above image, the amount is set to 12 for encoding, and -12 for decoding.

var caesarShift = function(str, amount) {

	// Wrap the amount
	if (amount < 0)
		return caesarShift(str, amount + 26);

	// Make an output variable
	var output = '';

	// Go through each character
	for (var i = 0; i < str.length; i ++) {

		// Get the character we'll be appending
		var c = str[i];

		// If it's a letter...
		if (c.match(/[a-z]/i)) {

			// Get its code
			var code = str.charCodeAt(i);

			// Uppercase letters
			if ((code >= 65) && (code <= 90))
				c = String.fromCharCode(((code - 65 + amount) % 26) + 65);

			// Lowercase letters
			else if ((code >= 97) && (code <= 122))
				c = String.fromCharCode(((code - 97 + amount) % 26) + 97);

		}

		// Append
		output += c;

	}

	// All done!
	return output;

};