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What does the following code output?
```java
int x = 5;
if (x > 3) {
System.out.println("A");
} else {
System.out.println("B");
}
```
`A`
What does the following code output?
```java
int x = 10;
if (x < 5 && x > 7) {
System.out.println("True");
} else {
System.out.println("False");
}
```
`False`
What does the following code output?
```java
String str1 = "hello";
String str2 = new String("hello");
if (str1.equals(str2)) {
System.out.println("Equal");
} else {
System.out.println("Not Equal");
}
```
`Equal`
What does the following code output?
```java
boolean a = true;
boolean b = false;
System.out.println(!a || b);
```
`false`
Identify the error in the following code:
```java
if (x = 5) {
System.out.println("x is 5");
}
```
The condition should use `==` for comparison, not `=` for assignment. It should be `if (x == 5)`.
What does the following code output?
```java
int score = 75;
if (score >= 90) {
System.out.println("A");
} else if (score >= 80) {
System.out.println("B");
} else if (score >= 70) {
System.out.println("C");
} else {
System.out.println("D");
}
```
`C`
What does the following code output?
```java
int num = 6;
if (num % 2 == 0 && num % 3 == 0) {
System.out.println("Divisible by 2 and 3");
} else {
System.out.println("Not divisible by 2 and 3");
}
```
`Divisible by 2 and 3`
What does the following code output?
```java
int age = 20;
String message = (age >= 18) ? "Adult" : "Minor";
System.out.println(message);
```
`Adult`
What does the following code output?
```java
String s1 = new String("Java");
String s2 = new String("Java");
System.out.println(s1 == s2);
```
`false`
What does the following code output?
```java
boolean x = false, y = true;
if (x = y) {
System.out.println("True");
} else {
System.out.println("False");
}
```
`True`
What is a Boolean expression?
An expression that evaluates to either `true` or `false`.
What is an `if` statement?
A conditional statement that executes a block of code only if a condition is `true`.
What is an `if-else` statement?
A conditional statement that executes one block of code if a condition is `true`, and another block if it's `false`.
What is an `if-else if-else` statement?
A conditional statement that creates multiple branches, allowing you to check a series of conditions.
What is the `==` operator?
Checks if two primitive values are equal.
What is the `!=` operator?
Checks if two values are not equal.
What is the `&&` operator?
The AND operator. Returns `true` only if both operands are `true`.
What is the `||` operator?
The OR operator. Returns `true` if at least one operand is `true`.
What is the `!` operator?
The NOT operator. Negates a boolean value.
What does `.equals()` do?
Compares the content of objects for equality.
What is branching in programming?
Branching is where a program takes different paths of execution based on conditions.
Why are boolean expressions important?
They are the foundation of all decision-making in programs, allowing code to react to different situations.
What is operator precedence?
The order in which operators are evaluated in an expression. `!` has higher precedence than `&&`, which has higher precedence than `||`.
Explain nested conditionals.
Putting `if` statements inside other `if` statements to create more complex logic.
What is a compound boolean statement?
A statement that combines multiple simple boolean expressions using logical operators.
Why should you use `.equals()` instead of `==` when comparing objects?
`==` checks if two references point to the same object, while `.equals()` checks if the objects have the same content.
What is the purpose of a `return` statement inside a conditional block?
It immediately exits the method, skipping any remaining code in the method.
What does it mean for boolean expressions to be equivalent?
They always evaluate to the same boolean value for all possible inputs.
How can truth tables be used in boolean logic?
Truth tables can be used to prove the equivalence of boolean expressions and to simplify complex logic.
What is the difference between a simple and compound boolean expression?
A simple boolean expression contains a single comparison, while a compound boolean expression combines multiple simple expressions with logical operators.