javascript.js

const display = document.querySelector(".calculator-display p");

document.querySelectorAll('.calculator-row button').forEach(button => {
  button.addEventListener('click', () => {
    const input = button.textContent;
    const operators = ['+', '−', '×', '/'];
    const lastChar = display.textContent.slice(-1);
    if (input === "=") {
      const match = display.textContent.match(/([0-9.]+)([+\−×/])([0-9.]+)/);
      if (match) {
        const [expression, num1, operator, num2] = match;
        const remaining = display.textContent.slice(expression.length); 
        const result = operate(operator, +num1, +num2);
        if (remaining) {
          display.textContent = result + remaining;
        } else {
          display.textContent = result;
        };
      };
    } else if (input === "C") {
      display.textContent = "0";
    } else if (display.textContent === "0") {
      display.textContent = input;
    } else {
      if (operators.includes(lastChar) && operators.includes(input)) {
        display.textContent = display.textContent.slice(0, -1) + input; 
      } else {
      display.textContent += input; 
      };
    };
  });
});

function operate(operator, num1, num2) {
  switch (operator) {
    case '+':
      return Math.round(num1 + num2);
    case '−':
      return Math.round(num1 - num2);
    case '×':
      return Math.round(num1 * num2);
    case '/':
      if (num2 === 0) {
        return "Cannot divide by 0";
      } else
      return Math.round(num1 / num2);
    default:
      return "Error";
  }
}