8-Dars Amaliyot: Kalkulyator yoki oddiy interaktiv ilova

Bu darsda biz JavaScript yordamida oddiy kalkulyator yaratamiz. Ilovamiz foydalanuvchidan ikkita son va amal (+, -, *, /) kiritishini so‘raydi va natijani chiqaradi.

1. Oddiy Konsol Kalkulyator

Birinchi bosqichda, prompt va switch-case yordamida konsol uchun kalkulyator yaratamiz.

function kalkulyator() {
    let son1 = parseFloat(prompt("Birinchi sonni kiriting:"));
    let amal = prompt("Amalni tanlang (+, -, *, /):");
    let son2 = parseFloat(prompt("Ikkinchi sonni kiriting:"));

    let natija;
    switch (amal) {
        case "+":
            natija = son1 + son2;
            break;
        case "-":
            natija = son1 - son2;
            break;
        case "*":
            natija = son1 * son2;
            break;
        case "/":
            natija = son2 !== 0 ? son1 / son2 : "0 ga bo‘lish mumkin emas!";
            break;
        default:
            natija = "Noto‘g‘ri amal!";
    }

    alert(`Natija: ${natija}`);
}

kalkulyator();

✅ Funktsional imkoniyatlar:

Foydalanuvchidan ikki son va amal so‘raydi.
Switch-case orqali amallarni bajaradi.
Bo‘lishda 0 ga bo‘lishni tekshiradi.
parseFloat — bu JavaScript-da string (matn) qiymatni o'nlik son (floating-point number) ga o‘zgartirish uchun ishlatiladigan funksiya. Agar matnda faqat son qismi bo‘lsa, parseFloat uni son sifatida qaytaradi. Agar matn boshqa belgilar bilan boshlangan bo‘lsa, NaN (Not a Number) qaytaradi.

2. HTML + JavaScript bilan Kalkulyator (Interaktiv Ilova)

Endi interaktiv veb-kalkulyator yaratamiz. HTML orqali input va button, JavaScript orqali esa hisob-kitoblarni bajaramiz.

📌 HTML va CSS kod

<!DOCTYPE html>
<html lang="uz">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Kalkulyator</title>
    <style>
        body {
            font-family: Arial, sans-serif;
            text-align: center;
            margin-top: 50px;
        }
        .container {
            width: 300px;
            margin: auto;
            padding: 20px;
            border: 2px solid #333;
            border-radius: 10px;
            box-shadow: 3px 3px 10px rgba(0, 0, 0, 0.2);
        }
        input, select, button {
            width: 100%;
            margin: 10px 0;
            padding: 10px;
            font-size: 16px;
        }
    </style>
</head>
<body>
    <div class="container">
        <h2>Kalkulyator</h2>
        <input type="number" id="son1" placeholder="Birinchi son">
        <select id="amal">
            <option value="+">Qo‘shish (+)</option>
            <option value="-">Ayirish (-)</option>
            <option value="*">Ko‘paytirish (*)</option>
            <option value="/">Bo‘lish (/)</option>
        </select>
        <input type="number" id="son2" placeholder="Ikkinchi son">
        <button onclick="hisobla()">Hisoblash</button>
        <h3>Natija: <span id="natija"></span></h3>
    </div>

    <script>
        function hisobla() {
            let son1 = parseFloat(document.getElementById("son1").value);
            let amal = document.getElementById("amal").value;
            let son2 = parseFloat(document.getElementById("son2").value);
            let natija;

            if (isNaN(son1) || isNaN(son2)) {
                natija = "Iltimos, son kiriting!";
            } else {
                switch (amal) {
                    case "+":
                        natija = son1 + son2;
                        break;
                    case "-":
                        natija = son1 - son2;
                        break;
                    case "*":
                        natija = son1 * son2;
                        break;
                    case "/":
                        natija = son2 !== 0 ? son1 / son2 : "0 ga bo‘lish mumkin emas!";
                        break;
                    default:
                        natija = "Noto‘g‘ri amal!";
                }
            }

            document.getElementById("natija").textContent = natija;
        }
    </script>
</body>
</html>

✅ Xususiyatlari:

HTML input orqali sonlar va amal tanlanadi.
Button bosilganda hisobla() funksiyasi ishga tushadi.
JavaScript hisob-kitoblarni bajaradi va Natija maydoniga chiqaradi.