Casting and Ranges of Variables
Emily Wilson
6 min read
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Study Guide Overview
This study guide covers data types and casting in Java. It reviews integer ranges, including Integer.MAX_VALUE and Integer.MIN_VALUE, and the concept of integer overflow. It explains widening (automatic) and narrowing (manual) casting between int and double types, emphasizing how truncation occurs during narrowing. Finally, it demonstrates how to use casting for rounding both positive and negative numbers.
#AP Computer Science A: Data Types & Casting - The Night Before 🚀
Hey there, future AP Computer Science A rockstar! Let's get you prepped and feeling confident for tomorrow. This guide is designed to be your ultimate review, hitting the key points you need to ace this exam. Let's dive in!
#1.2: Data Types and Variables
#Integer Ranges
- Remember, integers in Java have limits!
- Integer.MAX_VALUE: The largest possible integer.
- Integer.MIN_VALUE: The smallest possible integer.
Going outside these bounds leads to integer overflow, which can cause unexpected results.
#Casting: Converting Between Data Types
- Sometimes, you need to mix integers and doubles in calculations. That's where casting comes in!
#Widening (Automatic Conversion): Integers to Doubles
- Java automatically converts (widens) an integer to a double when needed.
- Example:
double a = 2 + 1;// a becomes 3.0
- Example:
#Narrowing (Manual Conversion): Doubles to Integers
- Converting a double to an integer requires a manual cast because it can lead to loss of precision.
Casting truncates (chops off) the decimal part, it does not round.
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