java.js

const calculatorContainer = document.getElementById('calculator_container');
const displayArea = document.getElementById('display_area');

calculatorContainer.addEventListener('click', (e) => {
    if (e.target.nodeName === 'BUTTON'){
        const text = e.target.textContent;
        switch (text){
            case 'C':
                clearDisplay();
                break;
                
            case 'DEL':
                deleteOneValue();
                break;
            case '=':
                evaluateExpression();
                break;
            default:
                addToDisplayArea(text);
        }
    }
});

function clearDisplay() {
    displayArea.textContent = '';
}

function addToDisplayArea(value){
    displayArea.textContent += value;
}

function deleteOneValue(){
    displayArea.textContent = displayArea.textContent.slice(0, -1);
}

function evaluateExpression(){
    try {
        const result = eval(displayArea.textContent);
        displayArea.textContent = String(result);
    } catch (err) {
        displayArea.textContent = 'Error';
        setTimeout(() => { displayArea.textContent = ''; }, 1000);
    }
}