Prof. Navrati Saxena TA: Rochak Sachan

Transcription

1 JAVA Prof. Navrati Saxena TA: Rochak Sachan

2 Operators

3 Operator Arithmetic Relational Logical Bitwise

4 1. Arithmetic Operators are used in mathematical expressions. S.N. 0 Operator Result 1. + Addition 6. += 2. Subtraction 7. = 3. * Multiplication 8. *= 4. / Division 9. /= 5. % Modulus 10. %= S.N. Operator Result Addition assignment Subtraction assignment Multiplication assignment Division assignment Modulus assignment 11. Decrement

5 Arithmetic Operators (Cont ) The operands of the arithmetic operators must be of a numeric type. Can not be used on boolean types, but you can use them on char types, since the char type in Java is a subset of int.

6 Basic Arithmetic Operators - addition, subtraction, multiplication, and division. // Demonstrates the basic arithmetic operators. class BasicMath { public static void main(string args[]) { int a = 1 + 1; int b = a * 3; int c = b / 4; int d = c - a; int e = -d; 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); } }

7 Modulus Operator (%) - returns the remainder of a division operation. - can be applied to floating-point types as well as integer types. (This differs from C/C++, in which the % can only be applied to integer types.)

8 Modulus Operator (%) // Demonstrates the % operator. class Modulus { public static void main(string args[]) { int x = 42; double y = 42.25; System.out.println("x mod 10 = " + x % 10); System.out.println("y mod 10 = " + y % 10); } }

9 Arithmetic Assignment Operators // Demonstrates several assignment operators. class OpEquals { public static void main(string args[]) { int a = 1; int b = 2; int c = 3; a += 5; b *= 4; c += a * b; c %= 6; System.out.println("a = " + a); System.out.println("b = " + b); System.out.println("c = " + c); } }

10 Increment and Decrement // Demonstrates ++. class IncDec { public static void main(string args[]) { int a = 1; int b = 2; int c; int d; c = ++b; d = a++; c++; System.out.println("a = " + a); System.out.println("b = " + b); System.out.println("c = " + c); System.out.println("d = " + d); } }

11 2. Bitwise Operators Java defines several bitwise operators which can be applied to the integer types, long, int, short, char, and byte.

12 Bitwise Operators S.N. Operator Result S.N. Operator Result 1. ~ Bitwise unary NOT 8. &= 2. & Bitwise AND 9. = 3. Bitwise OR 10. ^= 4. ^ Bitwise exclusive OR 11. >>= 5. >> Shift right 12. >>>= 6. >>> Shift right zero fill 13. <<= Bitwise AND assignment Bitwise OR assignment Bitwise exclusive OR assignment Shift right assignment Shift right zero fill assignment Shift left assignment 7. << Shift left

13 Bitwise Logical Operators (&,, ^, and ~.) - The following table shows the outcome of each operation. A B A B A & B A ^ B ~A

14 The Left Shift (<<) shifts all of the bits in a value to the left a specified number of times. It has the general form: value << num num specifies the number of positions to left-shift the value in value. For each shift left, the high-order bit is shifted out (and lost), and a zero is brought in on the right. Each left shift has the effect of doubling the original value.

15 The Right Shift (>>) shifts all of the bits in a value to the right a specified number of times. It has the general form: value >> num num specifies the number of positions to right-shift the value in value. When shifting right, the top (leftmost) bits exposed by the right shift are filled in with the previous contents of the top bit. Each time you shift a value to the right, it divides that value by two and discards any remainder.

16 3. Relational Operators - The relational operators determine the relationship that one operand has to the other. S.N. Operator Result S.N. Operator Result 1. == Equal to 4. < Less than 2.!= Not equal to 5. >= 3. > Greater than 6. <= Greater than or equal to Less than or equal to

17 3. Relational Operators The outcome of these operations is a boolean value. Most frequently used in the expressions that control the if statement and the various loop statements. Example: int a = 4; int b = 1; boolean c = a < b; In this case, the result of a<b (which is false) is stored in c.

18 4. Boolean Logical Operators operate only on boolean operands. All of the binary logical operators combine two boolean values to form a resultant boolean value.

19 4. Boolean Logical Operators S.N. Operator Result S.N. Operator 1. & Logical AND 7. &= 2. Logical OR 8. = 3. ^ Logical XOR (exclusive OR) 9. ^= Result AND assignment OR assignment XOR assignment 4. Short-circuit OR 10. == Equal to 5. && Short-circuit AND 11.!= Not equal to 6.! Logical unary NOT 12.?: Ternary if-thenelse

20 4. Boolean Logical Operators The following table shows the effect of each logical operation: A B A B A & B A ^ B!A False False False False False True True False True False True False False True True False True True True True True True False False

21 Short-Circuit Logical Operators (, &&) If you use the and && forms, rather than the and & forms of these operators, Java will not bother to evaluate the righthand operand when the outcome of the expression can be determined by the left operand alone. Example: if (denom!= 0 && num / denom > 10) *there is no risk of causing a run-time exception when denom is zero.

22 The? Operator (three-way) operator that can replace certain types of if-then-else statements. The? has this general form: expression1? expression2 : expression3 - If expression1 is true, then expression2 is evaluated; otherwise, expression3 is evaluated. - Both expression2 and expression3 are required to. return the same type, which can t be void.

23 Operator Precedence This part of the presentation shows the order of precedence for Java operators, from highest to lowest. Parentheses are used to alter the precedence of an operation. Parentheses raise the precedence of the operations that are inside them.

24 Operator Precedence Highest Lowest ( ) [ ]. ++ ~! * / % + >> >>> << > >= < <= ==!= & ^ &&?: = op= Table. The Precedence of the Java Operators

25 References Herbert Schildt; "Java The Complete Reference, Seventh Edition (Osborne Complete Reference Series)", McGraw- Hill, ogjava.htm m

26 Thank You