Programming Tutorials

Operators in java

By: aathishankaran in Java Tutorials on 2007-02-01  

Programs are required to perform a lot more than just simple input and output operations. All computer languages provide tools for some predefined operations. These tools are known as operators. The types of operators are:

• Arithmetic operators
• Relational operators
• Logical operators

Arithmetic operators

Arithmetic operations commonly performed are:

• Addition (+)
• Subtraction (-)
• Multiplication (*)
• Division (/)

The symbols representing arithmetic operations are called arithmetic operators.

Another operator is used to find the reminder when one integer is divided by another. This is called the modulo operator and is represented as %

Precedence of execution follows the same rule as in mathematics (Division, Multiplication, Addition, Subtraction). Precedence can be changed using parenthesis.

The complete pseudo code to calculate distance for a given speed and time can be written as follows:

//Program to calculate distance

PROGRAM_DISTANCE
{
  integer Distance, Speed, Time;
  Distance = 0;
  accept Speed;
  accept Time;
  Distance = Speed * Time;
  Display Distance;
}

Relational Operators

Relational Operators are used to test the relationship between two variables, or between a variables, or between a variable and a constant. The test for equality, for example, is made by means of two adjacent equal signs, with no space separating them. The six relational operators are:

The expression (Number ==7 ) means: “Is the value contained in the value contained in the variable Number equal to 7?†The answer to this question is either yes or no(also evaluated as true or false).

Logical Operators

Logical operators are used to combine or negate expressions containing relational operators relational operators. For example, you want a program to perform certain steps if the variable, Number, is equal to 7, and another variable, Num_two, is greater that 5. to code this type of expression, the logical operator AND is used in conjunction with the relational operator == ( Number == 7 AND Num_two >5). The compound condition combined with the AND operator evaluates to true only if all the individual conditions evaluate to true.

The logical operator OR is used when at least one of the conditions must be true in order to satisfy the compound condition.

The logical operator NOT reverses the result of a condition. If the condition results in true, the NOT operator makes it false; and the if construct is framed using relational operators.

Logical operators can be used to specify the compound condition.

Precedence of execution of logical operators are: NOT, AND, OR. However, using parenthesis can change the precedence of execution.