jasonkeene · August 29, 2015 13:56
diff --git a/calc.html b/calc.html
 <!DOCTYPE html>
 <html>
 <head>
 <title>Testing Calculator</title>

 <style type="text/css">
 #display {
    width: 180px;
    border: 1px solid black;
    padding: 5px 7px;
    text-align: right;
    font-family: "Courier New", Courier, "Lucida Sans Typewriter", "Lucida Typewriter", monospace;
 }
 input[type=button] {
    font-size: 14px;
    width: 40px;
    margin: 3px;
 }
 </style>

 </head>
 <body>


 <div id="display"></div>

 <input type="button" id="clear" value="AC" />

 <br />

 <input type="button" id="number-7" value="7" />
 <input type="button" id="number-8" value="8" />
 <input type="button" id="number-9" value="9" />
 <input type="button" id="divide" value="/" />

 <br />

 <input type="button" id="number-4" value="4" />
 <input type="button" id="number-5" value="5" />
 <input type="button" id="number-6" value="6" />
 <input type="button" id="multiply" value="*" />

 <br />

 <input type="button" id="number-1" value="1" />
 <input type="button" id="number-2" value="2" />
 <input type="button" id="number-3" value="3" />
 <input type="button" id="subtract" value="-" />

 <br />

 <input type="button" id="number-0" value="0" />
 <input type="button" id="decimal" value="." />
 <input type="button" id="evaluate" value="=" />
 <input type="button" id="add" value="+" />

 <script src="http://code.jquery.com/jquery-1.11.0.min.js"></script>
 <script type="text/javascript">
 $(function () {
    var display = $('#display'),
        buttons = $('input[type=button]'),
        state = 0, // this is the current value of the calculator
        register = null, // this holds the temporary value the user is inputing
        operator = null, // this holds the currently selected operator
        operator_map;

    // refresh the display (gets called after any input)
    function paint_display() {
        // if register is set, display it's value, else fall back to state
        display.text(register || state);
    }

    // evaluate the current operator and update calculator state
    function evaluate() {
        // this function requires an operator and two operands, state and
        // register (state is always set).
        if (operator !== null && register !== null) {
            state = operator(state, parseFloat(register));
            register = null;
            operator = null;
        }
    }

    // clear all calculator state
    function clear() {
        state = 0;
        register = null;
        operator = null;
    }

    // store all operators in a map for easy lookup
    operator_map = {
        "/": function div(a, b) {
            return a / b;
        },
        "*": function mult(a, b) {
            return a * b;
        },
        "+": function add(a, b) {
            return a + b;
        },
        "-": function sub(a, b) {
            return a - b;
        }
    };

    // handle user input (keypress and button clicks)
    function handle_input(input) {
        switch (input) {
            case "0":
            case "1":
            case "2":
            case "3":
            case "4":
            case "5":
            case "6":
            case "7":
            case "8":
            case "9":
                // if register isn't set then set it to empty string
                register = register || "";
                // string concat the input at the end of the register
                register = register + input;
                break;
            case ".":
                // if register isn't set then set it to "0"
                register = register || "0";
                // add a '.' at the end of register if there isn't already one
                register = register.indexOf('.') < 0 ? register + '.' : register;
                break;
            case "/":
            case "*":
            case "+":
            case "-":
                // evaluate previous operators so you can chain them w/o
                // requiring user to hit =
                evaluate();
                // if there is still a value in register after evaluating then
                // set it as the new state
                if (register !== null) {
                    state = parseFloat(register);
                    register = null;
                }
                // set the new operator
                operator = operator_map[input];
                break;
            case "=":
                evaluate();
                break;
            case "AC":
                clear();
                break;
        }

        // finally refresh the display
        paint_display();
    }

    // handler for the click event on any buttons
    buttons.click(function (e) {
        e.preventDefault();
        handle_input(e.target.value);
    });
    // handler for keypress on body
    $("body").keypress(function (e) {
        var charCode = e.charCode || e.keyCode || e.which;
        e.preventDefault();
        switch (charCode) {
            case 13:
                // charCode 13 (return key) converts into "="
                handle_input("=");
                break;
            default:
                // all other keys get mapped directly to their string value
                handle_input(String.fromCharCode(charCode));
                break;
        }
    });

    // after setup display the init state (0)
    paint_display();
 });
 </script>

 </body>
 </html>
	<!DOCTYPE html>
	<html>
	<head>
	<title>Testing Calculator</title>

	<style type="text/css">
	#display {
	width: 180px;
	border: 1px solid black;
	padding: 5px 7px;
	text-align: right;
	font-family: "Courier New", Courier, "Lucida Sans Typewriter", "Lucida Typewriter", monospace;
	}
	input[type=button] {
	font-size: 14px;
	width: 40px;
	margin: 3px;
	}
	</style>

	</head>
	<body>


	<div id="display"></div>

	<input type="button" id="clear" value="AC" />

	<br />

	<input type="button" id="number-7" value="7" />
	<input type="button" id="number-8" value="8" />
	<input type="button" id="number-9" value="9" />
	<input type="button" id="divide" value="/" />

	<br />

	<input type="button" id="number-4" value="4" />
	<input type="button" id="number-5" value="5" />
	<input type="button" id="number-6" value="6" />
	<input type="button" id="multiply" value="*" />

	<br />

	<input type="button" id="number-1" value="1" />
	<input type="button" id="number-2" value="2" />
	<input type="button" id="number-3" value="3" />
	<input type="button" id="subtract" value="-" />

	<br />

	<input type="button" id="number-0" value="0" />
	<input type="button" id="decimal" value="." />
	<input type="button" id="evaluate" value="=" />
	<input type="button" id="add" value="+" />

	<script src="http://code.jquery.com/jquery-1.11.0.min.js"></script>
	<script type="text/javascript">
	$(function () {
	var display = $('#display'),
	buttons = $('input[type=button]'),
	state = 0, // this is the current value of the calculator
	register = null, // this holds the temporary value the user is inputing
	operator = null, // this holds the currently selected operator
	operator_map;

	// refresh the display (gets called after any input)
	function paint_display() {
	// if register is set, display it's value, else fall back to state
	display.text(register \|\| state);
	}

	// evaluate the current operator and update calculator state
	function evaluate() {
	// this function requires an operator and two operands, state and
	// register (state is always set).
	if (operator !== null && register !== null) {
	state = operator(state, parseFloat(register));
	register = null;
	operator = null;
	}
	}

	// clear all calculator state
	function clear() {
	state = 0;
	register = null;
	operator = null;
	}

	// store all operators in a map for easy lookup
	operator_map = {
	"/": function div(a, b) {
	return a / b;
	},
	"*": function mult(a, b) {
	return a * b;
	},
	"+": function add(a, b) {
	return a + b;
	},
	"-": function sub(a, b) {
	return a - b;
	}
	};

	// handle user input (keypress and button clicks)
	function handle_input(input) {
	switch (input) {
	case "0":
	case "1":
	case "2":
	case "3":
	case "4":
	case "5":
	case "6":
	case "7":
	case "8":
	case "9":
	// if register isn't set then set it to empty string
	register = register \|\| "";
	// string concat the input at the end of the register
	register = register + input;
	break;
	case ".":
	// if register isn't set then set it to "0"
	register = register \|\| "0";
	// add a '.' at the end of register if there isn't already one
	register = register.indexOf('.') < 0 ? register + '.' : register;
	break;
	case "/":
	case "*":
	case "+":
	case "-":
	// evaluate previous operators so you can chain them w/o
	// requiring user to hit =
	evaluate();
	// if there is still a value in register after evaluating then
	// set it as the new state
	if (register !== null) {
	state = parseFloat(register);
	register = null;
	}
	// set the new operator
	operator = operator_map[input];
	break;
	case "=":
	evaluate();
	break;
	case "AC":
	clear();
	break;
	}

	// finally refresh the display
	paint_display();
	}

	// handler for the click event on any buttons
	buttons.click(function (e) {
	e.preventDefault();
	handle_input(e.target.value);
	});
	// handler for keypress on body
	$("body").keypress(function (e) {
	var charCode = e.charCode \|\| e.keyCode \|\| e.which;
	e.preventDefault();
	switch (charCode) {
	case 13:
	// charCode 13 (return key) converts into "="
	handle_input("=");
	break;
	default:
	// all other keys get mapped directly to their string value
	handle_input(String.fromCharCode(charCode));
	break;
	}
	});

	// after setup display the init state (0)
	paint_display();
	});
	</script>

	</body>
	</html>