script.js

let currentInput = "";
let isResultShown = false;

function appendToDisplay(value) {
  if (isResultShown) {
    document.getElementById("display").value = "";
    isResultShown = false;
  }
  currentInput += value;
  document.getElementById("display").value = currentInput;
}

function clearDisplay() {
  currentInput = "";
  document.getElementById("display").value = "";
}

function calcResult() {
  try {
    const result = eval(currentInput);
    document.getElementById("display").value = result;
    isResultShown = true;
    currentInput = result.toString();
  } catch (error) {
    document.getElementById("display").value = "Error";
  }
}

function deleteLast() {
  if (isResultShown) {
    clearDisplay();
  } else {
    currentInput = currentInput.slice(0, -1);
    document.getElementById("display").value = currentInput;
  }
}

function calcPercentage() {
  try {
    const percentage = eval(currentInput) / 100;
    document.getElementById("display").value = percentage;
    isResultShown = true;
    currentInput = percentage.toString();
  } catch (error) {
    document.getElementById("display").value = "Error";
  }
}