Conditions in Java

First…Boolean Operators

• A boolean data type is always true or false.

• Boolean operators always return true or false

• For example:

(x >y) asks “Is x bigger then y”?

Operators in Java

x > y Is x greater then y?

x < y Is x less then y?

x>=y Is x greater then or equal to y?

x<=y Is x less then or equal to y?

x==y Is x equal to y?

The “if” statement

Your program is going along, and you need to make a decision, a fork in the road…

?

The if statement

In Java the if statement works like this:

program…

if( some condition ){

come in here!

}

program

For example

if (grade < 50){

c.print(“You fail”);

}

//the program will only go inside the if block

//if the grade is less then 50

Note: Don’t put semicolons on if statements!

If else

• Sometimes you want to specify another path if the condition is not met.

• For this you would use else.

if(grade<50){c.print(“You fail”);

}else{

c.print(“you pass”); }

Conjunctives

• Two conditions can be linked together using conjunctives:

AND OR

Ex if(4<x AND x<10)

Sometimes you want the opposite of a condition,

Ex: if ( x is not equal to 4)

Symbols

AND &&

OR ||

Not !

For example

Let A and B be two conditions.

A and B (A && B)

A or B (A || B)

Not A (!A)

Not (A and B) !(A &&B)

Now Try A3!