Java if statement | |

Java if-else statement | |

Java nested if-else | |

Java else-if ladder | |

Java Switch case statement | |

Java Nested Switch Case | |

Java Ternary/Conditional operator |

Java while loop | |

Java do-while loop | |

Java for loop | |

Java Enhanced loop/for each loop | |

Java Labelled for loop | |

Java Nesting of loops | |

Java Break and Continue |

Java Programs | |

Java Keywords Dictionary | |

Java Interview Questions | |

An operator is a `symbol`

that indicated operations to be performed on variables. Operators are used in programs to manipulate data and variables.

**Operators are classified into following categories**

- Arithmetic operators
- Logical operators
- Relational operators
- Assignment operators
- Increment/Decrement operator
- Conditional operators

Arithmetic operators are used to perform on `Mathematical`

expressions and the computations.

**Following list shows the different Arithmetic operators**

Operator | Meaning of operator |
---|---|

+ | Addition or unary plus |

- | Subtraction or unary minus |

* | Multiplication |

/ | Division |

% | Modulus or remainder |

We are getting values from user throw commandline argument

when an expression contains both integer values then expression is called as `Integer expression`

.

Ex- 12 + 30

when both the operands in the expression are real, then the expression is called `Real arithmetic`

.

Ex- 12.3 + 66.32

when both the operands are of the different types then expression is called as `Mixed mode arithmetic`

.

Ex- 3.14 + 55

The logical operators are the operators which are used to form

conditions by combining two or more relations.**multiple**

Logical expression gives `true`

or `false`

value, based on expression.

- AND (
**&&**) Operator - OR (
**||**) Operator - NOT (
**!**) Operator

Logical AND is used when we want to check for both conditions to be same. It returns true when both the conditions are same otherwise returns false.

Logical OR is used when we want to check for only one condition to be true. It returns true when anyone condition becomes true .

It negates the result of expression from non zero to zero. It makes the result as true.

Operator | Meaning of operator | Example | Result |
---|---|---|---|

&& | Logical AND | ((10 < 20) && (10 > 50)) | false |

|| | Logical OR | ((30 < 20) || (30 > 5)) | true |

! | Logical NOT | (! (50 > 100)) | true |

**Truth table of Logical Operators (true = T , false = F)**

Operand 1 | Operand 2 | && | || |
---|---|---|---|

T | T | T | T |

T | F | F | T |

F | T | F | T |

F | F | F | F |

Comparing the above numbers by logical operators using if-else statement.

class ArithOperations { public static void main(String args[]) { int first, second; first = Integer.parseInt(arg[0]); second = Integer.parseInt(arg[1]); System.out.println("Addition : "+ (first + second)); System.out.println("Subtraction : "+ (first - second)); System.out.println("Multiplication : "+ (first * second)); System.out.println("Division : "+ (first / second)); } }

Addition : 90

Subtraction : 30

Multiplication : 1800

Division : 2

Subtraction : 30

Multiplication : 1800

Division : 2

When the comparison between two quantities is performed depending on their `relation`

, certain decisions are made.

Ex- If we compare salaries of two persons for finding who have more salary then relational operators are used.

The value of relational expression is either `true`

or `false`

. Java supports 6 relational operators as below

Operator | Operator Meaning | Example | Result |
---|---|---|---|

< | Less than | 20 < 10 | true |

> | Greater than | 20 > 10 | true |

== | Equals to | 33 == 44 | false |

<= | Less than or equals to | 50 <= 90 | true |

=> | Greater than or equals to | 68 => 90 | false |

!= | Not equals to | 50 != 90 | true |

Assignment operators are used to assign the value of an expression to a variable. Assignment operator ‘ **=** ‘ is used in the program for assignment.

NOTE : = and = = are different operators, we are using single = for assignment. |

variable = value;

**Assume B = 5**

Simple Assignment | Shorthand Assignment | Result |
---|---|---|

B = B + 1 | B += 1 | 6 |

B = B - 1 | B -= 1 | 5 |

B = B * (1+1) | B += (1+1) | 7 |

B = B / (1+1) | B /= (1+1) | 5 % 2 |

B = B % 5 | B %= 5 | 5 % 5 |

- Repetition is avoided
- Statement becomes more simple and short
- It results in more useful code
- Very easy to read

The increment (double `++`

) adds one or `increments`

the value by `1`

. And the decrement (double `--`

) subtracts or `decrements`

the value by `1`

**Increment and Decrement has following forms**

Operator | Meaning | What it does? |
---|---|---|

C++ | Post increment | First prints the value then increments C by 1 |

++C | Pre increment | First increments the value by 1 then prints C |

C-- | Post increment | First Prints the value then decrements C by 1 |

--C | Pre increment | First decrements the C by 1 then prints value |

The conditional operator (`?`

) is a ternary operator in java, which is used to construct conditional expression.

We will see in more detail in Decision making chapter.