Boolean & Equality Operators

Boolean Operators

There are 3 main boolean operators in Java (AND, OR, NOT). These operators are used to create conditions which will be used later.

Conditions are statements that are created by the programmer which evaluate to either true or false

The OR Operator (||)

Given 2 Booleans, the || operator can be used to see if either of the Booleans are true. This is illustrated in the table below:

boolean x = true;
boolean y = false;
boolean result = x || y; // true

boolean x = false;
boolean y = false;
boolean result = x || y; // false

The AND Operator (&&)

Given 2 Booleans, the && operator can be used to see if both of the 2 Booleans are true. This is illustrated in the table below:

boolean x = true;
boolean y = false;
boolean result = x && y;// false

boolean x = true;
boolean y = true;
boolean result = x && y; // true

The NOT Operator (!)

The NOT operator is special as it only uses 1 boolean, the operator inverts whatever boolean is inputted into it. This is illustrated in the table below:

boolean x = !false; // Not False: True
boolean y = !x; // Not True: False

Equality Operators

Equality operators are used to create conditions. You can check if two variables are equal, not equal, or if one is greater than the other. Equality operators will evaluate to either true or false. Similar to the boolean operators explained above

These operators are often used on Booleans, Integers, and Doubles

• x != y
  • If x does not equal y: will evaluate to true
• x == y
  • if x equals y: will evaluate to true

These operators are often used on Integers and Doubles.

• x > y
  • if x is greater than y: will evaluate to true
• x < y
  • if y is greater than x: will evaluate to true
• x <= y
  • if y is greater than or equal to x: will evaluate to true
• x >= y
  • if x is greater than or equal to y: will evaluate to true

Keep in mind that x and y don’t have to be variables, they could be integers, doubles, strings, etc.

Let’s look at a few examples of equality operators in action:

int x = 3;
double y = 4.1;
boolean z = x > y; // False, 4.1 > 3
boolean = (y - 3) > 1; // True, 1.1 > 1 

boolean x = false;
boolean y = false;
boolean result = (x == y); // true, false == false

It’s good practice to use parenthesis to separate the arithmetic from an equality operator, such as in the example above.