Operators in java Operator operands.

Transcription

1 Operators in java Operator in java is a symbol that is used to perform operations and the objects of operation are referred as operands. There are many types of operators in java such as unary operator, arithmetic operator, relational operator, shift operator, bitwise operator, ternary operator and assignment operator.

2 Operators [] () L to R Precedence postfix expr++ expr-- (R to L) unary ++expr --expr +expr -expr ~! (R to L) multiplicative * / % additive + - shift << >> relational Equality, NON-EQUALITY ==!= bitwise AND bitwise exclusive OR bitwise inclusive OR logical AND < > <= >= instance of & ^ && logical OR ternary? : assignment = += -= *= /= %= &= ^= = <<= >>= >>>=

3 Interger Arithmatic and Real Arithmatic class IntA { public static void main (String args [ ] ) { int a = 14, b= 4; System.out.println ("a = " + a) ; System.out.println (" b = " + b) ; System.out.println ("a+b = " + (a+b)) ; System.out.println (" a-b = " + (a-b)) ; System.out.println (" a*b = " + (a*b)) ; System.out.println (" a/b = " + (a/b) ); System.out.println (" a%b = " + (a%b)) ; } }

4 Interger Arithmatic and Real Arithmatic class reala { public static void main (String args [ ] ) { float a = 20.5F, b= 6.4F; System.out.println ("a = " + a) ; System.out.println (" b = " + b) ; System.out.println ("a+b = " + (a+b)) ; System.out.println (" a-b = " + (a-b)) ; System.out.println (" a*b = " + (a*b)) ; System.out.println (" a/b = " + (a/b) ); System.out.println (" a%b = " + (a%b)) ; } }

5 Relational Operators Meaning < Is less than <= Is less than or equal to > Greater than >= Greater than or equal to = = Is equal to (equality op)! Is Not equal to

6 INCREMENT / DECREMENT OPERATORS(++, - -) These operators usually not found in other languages. C++ name itself is influenced by the increment operator ++. The operator ++ adds 1 to its operand, and - - subtracts one.

7 a = a+1; is same as ++a ; or a++; And a=a-1; is same as - - a; or a - - ;

8 Both the increment and decrement operators come in two forms: 1. Prefix ( e.g. ++a and - - a) precede the operand 2. Postfix ( e.g. a++ and a- -) comes after the operand The two versions have the same effect upon the operand, but they differ when they take place in expression.

9 Working with prefix version When an increment or decrement operator precedes its operand, C++ performs the increment or decrement before using the value of the operand. For example, The expression sum = sum +(++count); Taking initial values of sum and count to be 0 and 10 respectively. sum= 0+(++count) sum = ; sum=11;

10 Similarly the expression p = p*- - n; Where initial value of p=4 and n=8; Evaluates as: p=4*7; p=28; p=4*(- - n); The prefix increment or decrement operators follow change- then-use rule. They first change the value of the operand, then use the new value in evaluating the expression.

11 Working with postfix version When an increment or decrement operator follows its operand, C++ performs the increment or decrement after using the value of the operand. For example, The expression sum = sum +(count++); Taking initial values of sum and count to be 0 and 10 respectively. sum= 0+(count++) sum = ; sum=10; // then count becomes 11

12 Similarly the expression p = p*n- -; Where initial value of p=4 and n=8; Evaluates as: p=4*8; p=4*(n- -); p=32; // now n becomes 7 The postfix increment or decrement operators follow use- then-change rule. They first use the value of the operand in evaluating the expression and then change the operand s value.

13 int Number=1000; Number++; //Post increment in an independent statement OR int Number=1000; ++Number; //Pre increment in an independent statement //will have the same meaning int Total=50,Number=10; Total=Total + Number++; //post increment - /* first the Total is increased by the current value of Number and then Number is incremented by 1 So, after execution of the expression Total will be 60 and Number will be 11 */

14 int Total=50,Number=10; Total=Total + ++Number; //pre-increment - //first the Number gets incremented //by 1 and then gets added to Total //So, after execution of the expression //Total will be 61 and Number will be 11

15 Conditional Operator?:

16 Conditional Operator?: (Ternary Operator) If the Exp1 evaluates to be true then Exp2 is evaluated and exp3 is ignored,otherwise Exp3 is evaluated and Exp2 is ignored. Exp1? Exp2: exp3 For example: Max= (a>b)? a: b;

17 Logical Operators (!, &&, ) Logical operators refers to the ways in which the relationships (among values) can be connected together. These are: 1. The logical AND (&&) operator 2. The logical OR ( ) operator 3. The logical NOT (!) operator

18 The logical AND (&&) operator The logical AND operators, written as &&, combines two expressions into one. The resulting expression has the value 1(true) only if both of the original expressions (its operands) are true. For example: (6==3) && (4==4) // 0(false) because exp1 is false (4==4) && (8==8) // 1(true) because both are true 6<9 && 4<2 // 0(false) exp2 is false 6>9 && 4>6 // 0(false) both false

19 The logical OR ( ) operator The logical OR operators, written as, combines two expressions into one. The resulting expression has the value 1(true) only if one or both of the original expressions (its operands) are true. For example: (6==3) (4==4) // 1(true) because exp2 is true (4==4) (8==8) // 1(true) because both are true 6<9 4<2 // 1(true) because exp1 is true 6>9 4>6 // 0(false) both false

20 The logical NOT (!) operator Works on single expression or operand ie. It is unary operator. It negates the the truth value of expression following it i.e., if the expression is true, then!expression is false, and vice versa.!(5) // 0(false) because 5 is non-zero(ie. True)!(5>2) // results in 0 because exp 5>2 is true i.e. 1

21 Shorthand Assignment operator: Operator Use Result += A+=B A= A+B *= A*=B A=A*B -= A-=B A=A-B /= A/=B A=A/B

22 Character Manipulation 1. When the operands are of Type String, + operator performs the concatenation. 2. In case of char literals, ASCII code is added for respective operands. 3. In case of numeric value we need to enclose them in () to make it expression. For Example: System.out.print( H + I ); System.out.print( A + a ); System.out.print( 5+7= +2+3); System.out.print( 5+7= +(2+3));

23 Evaluation of arithmetic operators I x= a-b/3 + c*2-1; When a= 9,b=12 and c=3 II x= a-b/ (3+c)*(2-1);

24 Evaluation of arithmetic operators I x= a-b/3 + c*2-1; When a= 9,b=12 and c=3 II x= a-b/ (3+c)*(2-1);

25 Bitwise operators Java defines several bitwise operators that can be applied to the integer types long, int, short, char and byte. operator description & Bitwise AND Bitwise OR ^ Bitwise exclusive OR << left shift >> right shift

26 truth table for bitwise &, and ^ a b a & b a b a ^ b ( A.B + A.B) The bitwise shift operators shifts the bit value. The left operand specifies the value to be shifted and the right operand specifies the number of positions that the bits in the value are to be shifted. Both operands have the same priority. Example a = b= 2 a << b= a >> b=