🕐Day 11 Java learning :

Great! Here's a clean, focused Day 11 Java learning note for you — about Data Type Conversion. I’ll cover:

• ✅ What it is
• ❓ Why we need it
• 🕐 When we use it
• 🔧 How to use it
• 🔄 All conversion paths (byte → short → int → long → float → double, etc.)

You can directly use this for your daily log or even turn it into a blog/PDF later!

📘 Day 11 — Java Data Type Conversion

🔹 What is Data Type Conversion in Java?

Data Type Conversion means converting one data type into another.

Java supports:

• ✅ Widening Conversion → done automatically
• ✅ Narrowing Conversion → needs manual casting

❓ Why Do We Need It?

• To store values in compatible types
• To perform operations between different data types
• To avoid errors during assignment or calculations
• To support method overloading, user input, etc.

🕐 When Do We Use It?

• During mathematical operations
• While assigning variables of different types
• When reading input (like from Scanner)
• In functions/methods that require specific types

🔧 How to Use It?

1. Widening Conversion (Automatic)

No cast needed — Java does it for you.

byte b = 10;
short s = b;   // byte → short
int i = s;     // short → int
long l = i;    // int → long
float f = l;   // long → float
double d = f;  // float → double

System.out.println(d);  // Output: 10.0

2. Narrowing Conversion (Manual)

You must cast manually. Risk of data loss.

double d = 99.99;
float f = (float) d;
long l = (long) f;
int i = (int) l;
short s = (short) i;
byte b = (byte) s;

System.out.println(b);  // Output: May lose precision

🔄 Full Widening Conversion Chart

✅ All above conversions are automatic (widening).

🔄 Full Narrowing Conversion Chart

✅ Final Tip:

Always prefer widening conversion when possible.

Use narrowing only when needed, and expect data loss or overflow.