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<!DOCTYPE html>
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<style>
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/* styles.css */
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body {
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font-family: Arial, sans-serif;
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display: flex;
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justify-content: center;
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align-items: center;
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height: 100vh;
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background-color: #f0f0f0;
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margin: 0;
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}
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.calculator {
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border: 1px solid #ccc;
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border-radius: 5px;
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box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
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background-color: #fff;
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padding: 20px;
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}
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.calculator-screen {
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width: 100%;
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height: 80px;
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border: none;
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background-color: #eee;
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text-align: right;
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font-size: 2em;
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padding: 20px;
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box-sizing: border-box;
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border-radius: 5px;
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margin-bottom: 10px;
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}
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.calculator-keys {
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display: grid;
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grid-template-columns: repeat(4, 1fr);
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gap: 10px;
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}
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button {
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height: 60px;
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font-size: 1.5em;
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border: none;
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border-radius: 5px;
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background-color: #eee;
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cursor: pointer;
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transition: background-color 0.3s;
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}
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button:hover {
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background-color: #aeaeae;
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}
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button.operator {
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background-color: #007BFF;
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color: #fff;
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}
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button.operator:hover {
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background-color: #0056b3;
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}
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button.all-clear, button.equal-sign {
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grid-column: span 2;
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background-color: #28a745;
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color: #fff;
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}
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button.all-clear:hover, button.equal-sign:hover {
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background-color: #218838;
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}
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</style>
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<html lang="en">
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<head>
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<meta charset="UTF-8">
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<meta name="viewport" content="width=device-width, initial-scale=1.0">
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<title>Simple Calculator</title>
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</head>
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<body>
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<div class="calculator">
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<input type="text" class="calculator-screen" value="" disabled />
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<div class="calculator-keys">
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<button type="button" class="operator" value="+">+</button>
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<button type="button" class="operator" value="-">-</button>
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<button type="button" class="operator" value="*">×</button>
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<button type="button" class="operator" value="/">÷</button>
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<button type="button" class="operator" value="%">%</button>
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<button type="button" value="7">7</button>
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<button type="button" value="8">8</button>
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<button type="button" value="9">9</button>
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<button type="button" value="4">4</button>
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<button type="button" value="5">5</button>
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<button type="button" value="6">6</button>
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<button type="button" value="1">1</button>
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<button type="button" value="2">2</button>
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<button type="button" value="3">3</button>
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<button type="button" value="0">0</button>
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<button type="button" class="decimal" value=".">.</button>
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<button type="button" class="all-clear" value="all-clear">AC</button>
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<button type="button" class="equal-sign operator" value="=">=</button>
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</div>
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</div>
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<script src="script.js"></script>
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</body>
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</html>
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<script>
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// script.js
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document.addEventListener('DOMContentLoaded', (event) => {
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const calculator = {
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displayValue: '0',
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firstOperand: null,
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waitingForSecondOperand: false,
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operator: null,
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};
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function updateDisplay() {
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const display = document.querySelector('.calculator-screen');
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display.value = calculator.displayValue;
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}
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const inputKeys = document.querySelector('.calculator-keys');
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inputKeys.addEventListener('click', (event) => {
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const { target } = event;
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const { value } = target;
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if (!target.matches('button')) {
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return;
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}
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switch (value) {
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case '+':
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case '-':
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case '*':
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case '/':
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case '%':
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if (calculator.waitingForSecondOperand) {
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calculate(calculator.firstOperand, calculator.displayValue, calculator.operator);
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} else {
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calculator.firstOperand = parseFloat(calculator.displayValue);
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calculator.waitingForSecondOperand = true;
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calculator.operator = value;
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}
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calculator.displayValue = '';
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break;
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case '=':
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if (calculator.waitingForSecondOperand) {
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calculate(calculator.firstOperand, calculator.displayValue, calculator.operator);
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}
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break;
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case '.':
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if (!calculator.displayValue.includes('.')) {
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calculator.displayValue += value;
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}
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break;
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case 'all-clear':
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calculator.displayValue = '0';
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calculator.firstOperand = null;
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calculator.waitingForSecondOperand = false;
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calculator.operator = null;
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break;
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default:
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if (Number.isInteger(parseFloat(value))) {
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if (calculator.displayValue === '0' && value !== '0') {
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calculator.displayValue = value;
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} else {
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calculator.displayValue += value;
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}
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}
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}
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updateDisplay();
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});
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function calculate(firstOperand, secondOperand, operator) {
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let result;
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const secondOperandNumber = parseFloat(secondOperand);
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switch (operator) {
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case '+':
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result = firstOperand + secondOperandNumber;
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break;
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case '-':
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result = firstOperand - secondOperandNumber;
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break;
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case '*':
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result = firstOperand * secondOperandNumber;
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break;
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case '/':
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result = firstOperand / secondOperandNumber;
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break;
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case '%':
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result = firstOperand % secondOperandNumber;
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break;
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default:
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return;
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}
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calculator.displayValue = result;
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calculator.firstOperand = result;
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calculator.waitingForSecondOperand = false;
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calculator.operator = null;
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}
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updateDisplay();
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});
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</script>
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