Arithmetic operators in java

The operands of the arithmetic operators must be of a numeric type. You cannot use them on boolean types, but you can use them on char types, since the char type in Java is, essentially, a subset of int.

List of arithmetic operators:

Operator	Result
+	Addition (also unary plus)
-	Subtraction (also unary minus)
*	Multiplication
/	Division
%	Modulus
++	Increment
+ =	Addition assignment
-=	Subtraction assignment
*=	Multiplication assignment
/=	Division assignment
%=	Modulus assignment
--	Decrement

Basic arithmetic operation

The basic arithmetic operations like addition, subtraction, multiplication, and division perform the same way as we read in mathematics.

The unary minus operator negates its single operand.

The unary plus operator simply returns the value of its operand.

public class BasicMathOperator {
  public static void main(String[] args) {
    int x = 3, y = 2;
    // arithmetic using integers
    System.out.println("Integer Arithmetic");
    int a = x + y;
    int b = x - y;
    int c = x * y;
    int d = x / y;
    int e = -x; // unary minus
    int f = +x; // unary plus
    System.out.println("a = " + a);
    System.out.println("b = " + b);
    System.out.println("c = " + c);
    System.out.println("d = " + d);
    System.out.println("e = " + e);
    System.out.println("f = " + f);

    // arithmetic using double
    System.out.println("\nFloating point Arithmetic");
    double da = x + y;
    double db = x - y;
    double dc = x * y;
    double dd = x / y;
    double de = -x; // unary minus
    double df = +x; // unary plus
    System.out.println("da = " + da);
    System.out.println("db = " + db);
    System.out.println("dc = " + dc);
    System.out.println("dd = " + dd);
    System.out.println("de = " + de);
    System.out.println("df = " + df);
  }
}

output:

Integer Arithmetic
a = 5
b = 1
c = 6
d = 1
e = -3
f = -3

Floating point Arithmetic
da = 5.0
db = 1.0
dc = 6.0
dd = 1.0
de = -3.0
df = 3.0

The Modulus Operator

The modulus operator, %, returns the remainder of a division operation. It can be applied to floating-point types as well as integer types.

// Demonstrate the % operator.
class Modulus {
  public static void main(String args[]) {
    int x = 35;
    double y = 47.67;
    System.out.println("x mod 10 = " + x % 10);
    System.out.println("y mod 10 = " + y % 10);
    System.out.println("x mod 9.8 = " + x % 9.8);
    System.out.println("y mod 9.8 = " + y % 9.8);
  }
}

output:

x mod 10 = 5
y mod 10 = 7.670000000000002
x mod 9.8 = 5.599999999999998
y mod 9.8 = 8.469999999999999

Arithmetic Compound Assignment Operators

You can combine arithmetic operator with an assignment.

Following are quite common in programming:

a = a + 10;

In Java, you can rewrite the satement as shown below:

a += 10;

This version uses the += compound assignment operator.

The compound assignment operators provide two benefits. First, they save you a bit of typing, because they are “shorthand” for their equivalent long forms. Second, in some cases they are more efficient than are their equivalent long forms.

Lets see an example of compound assignment operator.

// demonstrate compound assignment operator
public class CompoundOperator {
  public static void main(String[] args) {
    int a = 1, b = 2;
    int c = 3, d = 4, e = 5;
    a += 10;
    b -= 4;
    c *= 3;
    d /= 6;
    e %= 3;

    System.out.println("a = " + a);
    System.out.println("b = " + b);
    System.out.println("c = " + c);
    System.out.println("d = " + d);
    System.out.println("e = " + e);
  }
}

output:

a = 11
b = -2
c = 9
d = 0
e = 2

Increment and Decrement

The ++ and the – – are Java’s increment and decrement operators.

The increment operator increases its operand by one. The decrement operator decreases its operand by one.

The statement x = x + 1; can be rewritten using increment operator like below:

x++;

The statement x = x - 1; can be rewritten using decremet operator like below:

x--;

x++ and x-- is called postfix form. ++x and --x is called prefix form.

In the prefix form, the operand is incremented or decremented before the value is obtained for use in the expression.

In postfix form, the previous value is obtained for use in the expression, and then the operand is modified.

// Demonstrate prefix and postfix form.
class IncDecDemo {
  public static void main(String args[]) {
    int a = 5;
    int b = 6;
    int c = a++; // c assign to 5
    int d = ++b; // d assign to 7
    System.out.println("Postfix form::");
    System.out.println("c = " + c);
    System.out.println("d = " + d);
    System.out.println("a = " + a);
    System.out.println("b = " + b);
    a = 10;
    b = 11;

    int e = a--; // e assign to 10
    int f = --b; // f assign to 10

    System.out.println("\nPrefix form::");
    System.out.println("e = " + e);
    System.out.println("f = " + f);
    System.out.println("a = " + a);
    System.out.println("b = " + b);
  }
}

output:

Postfix form::
c = 5
d = 7
a = 6
b = 7

Prefix form::
e = 10
f = 10
a = 9
b = 10

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