Day 5: Understanding Java Operators

What is an Operator in Java?

In Java, an operator is a special symbol or keyword used to perform operations such as:

• Addition
• Subtraction
• Division
• Comparison
• Logical checking

Important terms:

• Operator → Symbol that performs an operation
• Operand → Value on which the operator works

Example:

int a = 10;

Here:

• = is the operator
• a and 10 are operands

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Types of Operators in Java

Java has the following operator types:

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1️⃣ Assignment Operator

Used to assign a value to a variable.

Operator:

=

Example:

int no = 10;

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2️⃣ Arithmetic Operators

Used to perform mathematical calculations.

Operators:

+, -, *, /, %

Examples:

int a = 10;
int b = 3;

System.out.println(a + b); // Addition
System.out.println(a - b); // Subtraction
System.out.println(a * b); // Multiplication
System.out.println(a / b); // Division
System.out.println(a % b); // Modulus (remainder)

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3️⃣ Unary Operators

Unary operators work on a single variable.

Increment Operator (++)

Used to increase value by 1.

=> Post Increment (no++)

• First use the value
• Then increase it

Example:

int no = 10;
System.out.println(no++); // 10
System.out.println(no);   // 11

=> Pre Increment (++no)

• First increase the value
• Then use it

Example:

int age = 15;
System.out.println(++age); // 16

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Decrement Operator (--)

Used to decrease value by 1.

=> Post Decrement (no--)

int no = 10;
System.out.println(no--); // 10
System.out.println(no);   // 9

=> Pre Decrement (--no)

int age = 15;
System.out.println(--age); // 14

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4️⃣ Equality and Relational Operators

Used to compare two values.

Operators:

== , != , < , > , <= , >=

Examples:

int a = 10;
int b = 20;

System.out.println(a == b); // false
System.out.println(a != b); // true
System.out.println(a < b);  // true

The result of these operators is always true or false.

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5️⃣ Conditional (Logical) Operators

Used to combine conditions.

Operators:

&&  (AND)
||  (OR)

=> AND operator (&&)

• Returns true only if both conditions are true

=> OR operator (||)

• Returns true if any one condition is true

Example:

int age = 20;
System.out.println(age > 18 && age < 60);