if statement examples in Java for High School: AP Computer Science A

📚 Quick Study Guide

• 🔍 An if statement executes a block of code only if a specified condition is true.
• 💡 The basic syntax is: `if (condition) { // code to execute }`
• 📝 You can add an else block to execute code when the condition is false: `if (condition) { // code if true } else { // code if false }`
• 🌱 Use else if to chain multiple conditions: `if (condition1) { // code 1 } else if (condition2) { // code 2 } else { // default code }`
• 🧱 Conditions use relational operators (==, !=, <, >, <=, >=) and logical operators (&&, ||, !).
• 🍎 Always use curly braces `{}` to define the code block, especially for multiple lines.
• 🔑 Nested `if` statements are allowed, placing an `if` statement inside another.

🧪 Practice Quiz

1. Which of the following is the correct syntax for an `if` statement in Java?
   1. `if condition then { code }`
   2. `if (condition) then { code }`
   3. `if condition { code }`
   4. `if (condition) { code }`
2. What will be the output of the following code? java int x = 5; if (x > 10) { System.out.println("x is greater than 10"); } else { System.out.println("x is not greater than 10"); }
   1. `x is greater than 10`
   2. `x is not greater than 10`
   3. No output
   4. Error
3. Which operator is used to check for equality in Java `if` statements?
   1. `=`
   2. `==`
   3. `!=`
   4. `>`
4. What does the `else` block do in an `if-else` statement?
   1. It executes code only if the condition is true.
   2. It executes code always.
   3. It executes code only if the condition is false.
   4. It defines a new condition.
5. What will be the output of the following code? java int age = 17; if (age >= 18) { System.out.println("Eligible to vote"); } else if (age >= 16) { System.out.println("Almost eligible"); } else { System.out.println("Not eligible to vote"); }
   1. `Eligible to vote`
   2. `Almost eligible`
   3. `Not eligible to vote`
   4. No output
6. Which of the following is a logical AND operator in Java?
   1. `||`
   2. `&&`
   3. `!`
   4. `&`
7. What happens if the condition in an `if` statement is always true?
   1. The code inside the `if` block never executes.
   2. The code inside the `if` block executes once.
   3. The code inside the `if` block executes repeatedly, creating an infinite loop if not handled carefully.
   4. It causes a compilation error.