Conditionals

COMP122 Lectures 2021-02-17

Imagine a program that does the following:

graph TD
i[Get Input]
i --> p[Positive?]
p -->|yes| Process
p -->|no| Complain
Process --> b[ ]
Complain --> b

if-else Statements in Java

if (condition) {
	// do stuff
}
else {
	// do something else
}

This means that if the condition holds the if bracket is executed and if not the else bracket is.

Relational Operators

The condition takes a boolean variable. Here are functions that take two inputs and return true or false:

Operator	Meaning
>	greater than
<	less than
==	equal to
>=	greater than or equal to
<=	less than or equal to
!=	not equal to

Boolean Operators

Operator	Meaning
!	NOT
&&	AND
||	OR
^	XOR

Initial Example

The initial example would be coded as follows:

int x = 5; // get input somehow

if (x > 0) {
	System.out.println("you gave me: " + x)
}
else {
	System.out.println(x + " is not positive!")
}