operators
An Operator is a symbol that allows a program to perform certain operation (like arithmetic or logical) on data and variables
1. Arithmetic (*, /, %, +, -, ++, --)
2. Assignment (=, +=, -=, *=, /=, %=)
3. Relational (==, !=, <, >, <=, >=)
4. Instance of (instance of)
5. Logical (&, &&, |, ||, ^, !)
6. Conditional (?:)
Depending on the no. of operands ,operator can be of the following three types
- Unary Operator: It takes one operand, such as ++x, y--. Here x and y are variables, while ++ and -- are operators.
- Binary Operator: It takes two operands, such as x + y, x > y. Here x and y are while + and > are operators.
- Ternary Operator: It takes three operands. z = x > y ? x : y. Here x, y and z are variables while ?: is an operator
Arithmetic operators
class Demo7{
public static void main(String[] args){
int i,j,k;
i = 30;
j = 20;
k = i + j;
System.out.println("Addition of i and j is " + k);
k = i - j;
System.out.println("Diff of i and j is " + k);
k = i * j;
System.out.println("Product of i and j is " + k);
k = i / j;
System.out.println("Division of i and j is " + k);
}
}
class Demo08{
public static void main(String[] args){
int num1 = 18;
int num2 = 4;
int quotient = num1 / num2;
int remainder = num1 % num2;
System.out.println("num1 / num2 = " + quotient);
System.out.println("num1 % num2 = " + remainder);
}
}
Assignment operators
The equal(=) symbol is known as the assignment operator. The assignment operator(=) is used to store or assign a value to a variable.
Eg: x = 10; // x stores 10 x = x + 10; // x stores 20 x = x + 5 * 20; // x stores 120 x = (x + 5) * 20; // x stores 2500
In compound assignment operator we have +=, -=, *=, /= and %=
Eg: i = 10 ; // i is initialized with the value 10 i += 15; // i is compound assigned with 25 (i = i + 15) i -= 5; // i is compound assigned with 20 (i = i - 5)
class Demo9{
public static void main(String[] args){
int i=2, j=3, k=4, l=25, m=7;
i += 25;
System.out.println(i);
j *= 6;
System.out.println(j);
k /= 2;
System.out.println(k);
l -= 10;
System.out.println(l);
m %= 5;
System.out.println(m);
}
}
Relational Operators
operator Description
== equal to
!= not equal to
< lesser than
> greater than
<= lesser than or equal to
>= greater than or equal to
class Demo10{
public static void main(String[] args){
int x = 5;
int y = 8;
int z = 10;
boolean b1 = x >= y;
boolean b2 = x >= y && z >=y;
System.out.println("b1= " + b1 + " b2= " + b2);
}
}
class Demo11{
static int i=10;
static int j=20;
public static void main(String[] args){
if(i == j){
System.out.println("the values " + i + "and " + j + "are equal");
}
if(i !=j){
System.out.println("the values " + i + "and " + j + "are not equal");
}
if(i < j){
System.out.println("the value " + i + " is lesser than " + j);
}
if(i > j){
System.out.println("the value " + i + " is greater than " + j);
}
}
}
Object equality
The relational equality operator (==) and (!=) can also used to compare the reference of the two objects
obj1 == obj2 // means that ob1 and obj2 are equal and have same object reference
instance of operator
The instance of a operator is a binary operator that checks whether an object is of a particular type(here, type can be class, interface or an array). It is used for object reference variable only
class Demo12{
public static void main(String[] args){
StringBuffer sb = new StringBuffer("Hello world");
if(sb instanceof StringBuffer){
System.out.println("sb is an instance of String buffer");
}else{
System.out.println("sb is not an instance of String Buffer");
}
}
}
Logical operators
Logical operators are && , ||, !, &, |. The operators || and && evaluate only boolean values. The not(!) operator returns the opposite of the current value of the boolean operand.
Conditional operators or ternary operand: The conditional operator (?:) is a ternary operator that takes three operands. It works similar to if-else statement.
ex: int i=20, j=25; boolean test = false; test = i > j ? true : false;
program:
class Demo14{
public static void main(String[] args){
int i = 20;
int j = 25;
boolean test = false;
test = i > j ? true :false;
System.out.println(test);
}
}
Unary Operators
- ++ increment operator (post increment, pre increment)
- -- decrement operator (post decrement, pre decrement)
int x = 5;
int j;
j = x++;
j = ++x;
class Demo15{
public static void main(String[] args){
System.out.println("Main starts");
int i = 0;
int j;
j = i++; // j = i; i=i+1;
System.out.println("i = " + i);
System.out.println("j = " + j);
System.out.println("Main ends");
}
}
class Demo16{
public static void main(String[] args){
System.out.println("Main starts");
int i=0;
int j=0;
System.out.println("i = " + i++);
System.out.println("i = " + i++);
System.out.println("i = " + i);
System.out.println("Main ends");
}
}
class Demo17{
public static void main(String[] args){
System.out.println("Main starts");
int i=0;
int j=0;
j = i + i++ + i + i++;
System.out.println("i = " + i);
System.out.println("j = " + j);
System.out.println("Main ends");
}
}
class Demo18{
public static void main(String[] args){
System.out.println("Main starts");
int i = 0;
int j = 0;
j = ++i;
System.out.println("i = " + i);
System.out.println("j = " + j);
System.out.println("Main ends");
}
}
class Demo19{
public static void main(String[] args){
System.out.println("Main starts");
int i = 0;
int j = 1;
int k = i + j++ + ++i + ++j + i++;
System.out.println("i = " + i);
System.out.println("j = " + j);
System.out.println("k = " + k);
System.out.println("Main ends");
}
}