script.js

const display = document.getElementById('display');
const buttons = document.querySelectorAll('.btn');
let currentInput = '';
let operator = '';
let firstNumber = '';
let secondNumber = '';
let hasDecimal = false;

buttons.forEach(button => {
  button.addEventListener('click', () => {
    const value = button.getAttribute('data-value');

    if (button.id === 'clear') {
      clearCalculator();
    } else if (button.id === 'equals') {
      calculateResult();
    } else if (button.classList.contains('operator')) {
      setOperator(value);
    } else {
      addInput(value);
    }
  });
});

function clearCalculator() {
  currentInput = '';
  operator = '';
  firstNumber = '';
  secondNumber = '';
  hasDecimal = false;
  display.textContent = '0';
}

function addInput(value) {
  if (value === '.' && hasDecimal) return; // Prevent adding more than one decimal point.
  
  if (value === '.') {
    hasDecimal = true;
  }
  
  currentInput += value;
  display.textContent = currentInput;
}

function setOperator(value) {
  if (currentInput) {
    firstNumber = currentInput;
    operator = value;
    currentInput = '';
    hasDecimal = false; // Reset decimal flag when moving to the next number
  }
}

function calculateResult() {
  if (firstNumber && operator && currentInput) {
    secondNumber = currentInput;
    const result = calculate(Number(firstNumber), Number(secondNumber), operator);
    display.textContent = result;
    currentInput = result.toString();
    firstNumber = '';
    operator = '';
    hasDecimal = result.toString().includes('.'); // Track if the result has a decimal
  }
}

function calculate(a, b, op) {
  switch (op) {
    case '+':
      return a + b;
    case '-':
      return a - b;
    case '*':
      return a * b;
    case '/':
      return b !== 0 ? a / b : 'Error'; // Division by zero check
    default:
      return 0;
  }
}