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Conditionals

& vs && and | vs ||

Key Differences
  • & and |: Bitwise operators (for numbers) or Logical operators (for booleans, no short-circuit).
  • && and ||: Logical operators (only for booleans, with short-circuiting).
Common Bug

Using & or | instead of && or || can cause hidden bugs:

int number = 0;
if (number != 0 & (10 / number) > 1) { // Crashes
    System.out.println("Safe division!");
}
❌ This crashes with a Division by zero error because & evaluates both sides.

int number = 0;
if (number != 0 && (10 / number) > 1) {
    System.out.println("Safe division!");
}
✅ No error, as && skips the second condition if the first is false.

Rule of Thumb
  • Use && and || for logical conditions (better for safety and performance).
  • Use & and | only when both sides must be evaluated (rare cases).

Ternary Operator (? :)

What is the Ternary Operator?

The ternary operator is a shorthand for if-else statements. It has the syntax:

condition ? value_if_true : value_if_false;
Example:

int a = 10, b = 20;
int max = (a > b) ? a : b; // Assigns the larger value to max
System.out.println("Max: " + max); // Output: Max: 20
When to Use
  • Use the ternary operator for simple conditional assignments.
  • Avoid using it for complex logic as it can reduce code readability.

Enhanced switch Expression (Java 12+)

What is the Enhanced switch?

The enhanced switch expression simplifies the syntax by removing the need for break statements and allows returning values directly. Example:

int day = 2;
String dayName;
switch (day) {
    case 1:
        dayName = "Monday";
        break;
    case 2:
        dayName = "Tuesday";
        break;
    default:
        dayName = "Unknown";
}
System.out.println(dayName); // Output: Tuesday


int day = 2;
String dayName = switch (day) {
    case 1 -> "Monday";
    case 2 -> "Tuesday";
    default -> "Unknown";
};
System.out.println(dayName); // Output: Tuesday
- The -> operator is used to define the case actions, eliminating the need for break statements.

When to Use
  • Use the enhanced switch for cleaner and more concise code.
  • It is especially useful when returning values directly from a switch.