Calculator/Calc.html at main · bspippi1337/Calculator · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Simple Calculator</title>
    <style>
        body {
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
            background-color: #f4f4f4;
            margin: 0;
        }

        .calculator {
            border: 1px solid #ccc;
            border-radius: 5px;
            padding: 20px;
            background-color: #fff;
            box-shadow: 0px 0px 10px rgba(0, 0, 0, 0.1);
        }

        .calculator-screen {
            width: 100%;
            height: 40px;
            margin-bottom: 10px;
            font-size: 24px;
            text-align: right;
            padding: 5px;
            border: 1px solid #ccc;
            border-radius: 5px;
        }

        .calculator-buttons {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 10px;
        }

        .button {
            width: 100%;
            height: 50px;
            font-size: 20px;
            border: 1px solid #ccc;
            border-radius: 5px;
            background-color: #e0e0e0;
            cursor: pointer;
        }

        .button:hover {
            background-color: #d4d4d4;
        }
    </style>
</head>
<body>
    <div class="calculator">
        <input type="text" class="calculator-screen" id="calculator-screen" disabled>
        <div class="calculator-buttons">
            <button class="button" onclick="clearScreen()">C</button>
            <button class="button" onclick="deleteChar()">DEL</button>
            <button class="button" onclick="appendChar('/')">/</button>
            <button class="button" onclick="appendChar('*')">*</button>
            <button class="button" onclick="appendChar('7')">7</button>
            <button class="button" onclick="appendChar('8')">8</button>
            <button class="button" onclick="appendChar('9')">9</button>
            <button class="button" onclick="appendChar('-')">-</button>
            <button class="button" onclick="appendChar('4')">4</button>
            <button class="button" onclick="appendChar('5')">5</button>
            <button class="button" onclick="appendChar('6')">6</button>
            <button class="button" onclick="appendChar('+')">+</button>
            <button class="button" onclick="appendChar('1')">1</button>
            <button class="button" onclick="appendChar('2')">2</button>
            <button class="button" onclick="appendChar('3')">3</button>
            <button class="button" onclick="calculateResult()">=</button>
            <button class="button" onclick="appendChar('0')">0</button>
            <button class="button" onclick="appendChar('.')">.</button>
        </div>
    </div>
    <script>
    const screen = document.getElementById("calculator-screen");

    function clearScreen() {
        screen.value = "";
    }

    function deleteChar() {
        screen.value = screen.value.slice(0, -1);
    }

    function appendChar(char) {
        screen.value += char;
    }

    function calculateResult() {
        const expression = screen.value;
        try {
            const result = evaluateExpression(expression);
            screen.value = result;
        } catch (e) {
            screen.value = "Error";
        }
    }

    function evaluateExpression(expression) {
        // This regex matches numbers (including decimals) and operators
        const tokens = expression.match(/(\d+\.?\d*)|[+\-*/]/g);
        if (!tokens) {
            return "";
        }

        // A simple function to perform a single calculation
        function performOperation(a, operator, b) {
            a = parseFloat(a);
            b = parseFloat(b);
            if (operator === '+') return a + b;
            if (operator === '-') return a - b;
            if (operator === '*') return a * b;
            if (operator === '/') {
                if (b === 0) throw new Error("Division by zero");
                return a / b;
            }
            throw new Error("Invalid operator");
        }

        // First pass: Multiplication and Division
        for (let i = 0; i < tokens.length; i++) {
            if (tokens[i] === '*' || tokens[i] === '/') {
                const result = performOperation(tokens[i - 1], tokens[i], tokens[i + 1]);
                // Replace the three elements with the result
                tokens.splice(i - 1, 3, result);
                i--; // Adjust index to account for the splice
            }
        }

        // Second pass: Addition and Subtraction
        let result = parseFloat(tokens[0]);
        for (let i = 1; i < tokens.length; i += 2) {
            result = performOperation(result, tokens[i], tokens[i + 1]);
        }

        return result;
    }
</script>

</body>
</html>