🏡 index : container_build.git

let operand;
let operation;
let displayString = '0';



function updateDisplay() {
  document.getElementById('display').value = displayString;
}

function addDigit(digit) {
  if (displayString === '0') {
    displayString = digit;
  } else {
    displayString += digit;
  }
  updateDisplay();
}

function doAddition() {
    operand = parseInt(displayString);
    displayString = '0';
    operation = '+';
}

function doSubtraction() {
    operand = parseInt(displayString);
    displayString = '0';
    operation = '-';
}

function doMultiplication() {
    operand = parseInt(displayString);
    displayString = '0';
    operation = '*';
}

function doDivision() {
    operand = parseInt(displayString);
    displayString = '0';
    operation = '/';
}

function doClear() {
    operand = undefined;
    operation = undefined;
    displayString = '0';
    updateDisplay();
}

function doEquals() {
    if (operand === undefined || operation === undefined) {
        return;
    }


    let secondOperand = parseInt(displayString);
    if (operation === '+') {
        displayString = operand + secondOperand;
    } else if (operation === '-') {
        displayString = operand - secondOperand;
    } else if (operation === '*') {
        displayString = operand * secondOperand;
    } else if (operation === '/') {
        displayString = operand / secondOperand;
    }

    operand = undefined;
    operation = undefined;
    updateDisplay();
    displayString = '0';
}

function keyPress(event) {
  if (event.key >= '0' && event.key <= '9') {
    addDigit(event.key);
  } else if (event.key === '+') {
    doAddition();
  } else if (event.key === '-') {
    doSubtraction();
  } else if (event.key === '*') {
    doMultiplication();
  } else if (event.key === '/') {
    doDivision();
  } else if (event.key === 'Enter') {
    doEquals();
  } else if (event.key === 'c') {
    doClear();
  }
}

document.addEventListener('keydown', keyPress);