• Saturday, May 6, 2017

    9. Java Operators

    Java Operators Flow Chart

    What is Java Operators?
    Operators are special symbols that perform specific operations on one, two, or three operands, and then return a result. As we explore the operators of the Java programming language, it may be helpful for you to know ahead of time which operators have the highest precedence.
    Java provides rich set of  operators to manipulates variable. Operators can be divided into following groups:-


    • Arithmetic Operator
    • Relational Operator
    • Bitwise Operator
    • Logical Operator
    • Assignment Operator
    • Misc Operator

    1. Arithmetic Operator

    Arithmetic Operator is used to perform mathematical calculation. Arithmetic operators are used in mathematical expressions in the same way that they are used in algebra. 


    OperatorDescriptionExample
    + (Addition)Adds values on either side of the operator.A + B will give 30
    - (Subtraction)Subtracts right-hand operand from left-hand operand.A - B will give -10
    * (Multiplication)Multiplies values on either side of the operator.A * B will give 200
    / (Division)Divides left-hand operand by right-hand operand.B / A will give 2
    % (Modulus)Divides left-hand operand by right-hand operand and returns remainder.B % A will give 0
    ++ (Increment)Increases the value of operand by 1.B++ gives 21
    -- (Decrement)Decreases the value of operand by 1.B-- gives 19

    2. Relational Operator

    Relation operator is used to check the relation between two operands( i.e. operand1 is equal to/ not equal to/ greater than/ smaller than  operand2)


    OperatorDescriptionExample
    == (equal to)Checks if the values of two operands are equal or not, if yes then condition becomes true.(A == B) is not true.
    != (not equal to)Checks if the values of two operands are equal or not, if values are not equal then condition becomes true.(A != B) is true.
    > (greater than)Checks if the value of left operand is greater than the value of right operand, if yes then condition becomes true.(A > B) is not true.
    < (less than)Checks if the value of left operand is less than the value of right operand, if yes then condition becomes true.(A < B) is true.
    >= (greater than or equal to)Checks if the value of left operand is greater than or equal to the value of right operand, if yes then condition becomes true.(A >= B) is not true.
    <= (less than or equal to)Checks if the value of left operand is less than or equal to the value of right operand, if yes then condition becomes true.(A <= B) is true.

    3. Bitwise Operator

    The Java programming language also provides operators that perform bitwise and bit shift operations on integral types. The operators discussed in this section are less commonly used. Therefore, their coverage is brief; the intent is to simply make you aware that these operators exist.

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

    Bitwise operator works on bits and performs bit-by-bit operation. Assume if a = 60 and b = 13; now in binary format they will be as follows −

    a = 0011 1100
    b = 0000 1101


    a&b = 0000 1100

    a|b = 0011 1101

    a^b = 0011 0001

    ~a  = 1100 0011

    OperatorDescriptionExample
    & (bitwise and)Binary AND Operator copies a bit to the result if it exists in both operands.(A & B) will give 12 which is 0000 1100
    | (bitwise or)Binary OR Operator copies a bit if it exists in either operand.(A | B) will give 61 which is 0011 1101
    ^ (bitwise XOR)Binary XOR Operator copies the bit if it is set in one operand but not both.(A ^ B) will give 49 which is 0011 0001
    ~ (bitwise compliment)Binary Ones Complement Operator is unary and has the effect of 'flipping' bits.(~A ) will give -61 which is 1100 0011 in 2's complement form due to a signed binary number.
    << (left shift)Binary Left Shift Operator. The left operands value is moved left by the number of bits specified by the right operand.A << 2 will give 240 which is 1111 0000
    >> (right shift)Binary Right Shift Operator. The left operands value is moved right by the number of bits specified by the right operand.A >> 2 will give 15 which is 1111
    >>> (zero fill right shift)Shift right zero fill operator. The left operands value is moved right by the number of bits specified by the right operand and shifted values are filled up with zeros.A >>>2 will give 15 which is 0000 1111

    4. Logical Operator


    A logical operator in Java programming is an operator that returns a Boolean result that’s based on the Boolean result of one or two other expressions.

    Sometimes, expressions that use logical operators are called “compound expressions” because the effect of the logical operators is to let you combine two or more condition tests into a single expression.

    OperatorDescriptionExample
    && (logical and)Called Logical AND operator. If both the operands are non-zero, then the condition becomes true.(A && B) is false
    || (logical or)Called Logical OR Operator. If any of the two operands are non-zero, then the condition becomes true.(A || B) is true
    ! (logical not)Called Logical NOT Operator. Use to reverses the logical state of its operand. If a condition is true then Logical NOT operator will make false.!(A && B) is true

    5. Assignment Operator

    Assignment operator is used to assign/modify values to a variable.

    OperatorDescriptionExample
    =Simple assignment operator. Assigns values from right side operands to left side operand.C = A + B will assign value of A + B into C
    +=Add AND assignment operator. It adds right operand to the left operand and assign the result to left operand.C += A is equivalent to C = C + A
    -=Subtract AND assignment operator. It subtracts right operand from the left operand and assign the result to left operand.C -= A is equivalent to C = C – A
    *=Multiply AND assignment operator. It multiplies right operand with the left operand and assign the result to left operand.C *= A is equivalent to C = C * A
    /=Divide AND assignment operator. It divides left operand with the right operand and assign the result to left operand.C /= A is equivalent to C = C / A
    %=Modulus AND assignment operator. It takes modulus using two operands and assign the result to left operand.C %= A is equivalent to C = C % A
    <<=Left shift AND assignment operator.C <<= 2 is same as C = C << 2
    >>=Right shift AND assignment operator.C >>= 2 is same as C = C >> 2
    &=Bitwise AND assignment operator.C &= 2 is same as C = C & 2
    ^=Bitwise exclusive OR and assignment operator.C ^= 2 is same as C = C ^ 2
    |=Bitwise inclusive OR and assignment operator.C |= 2 is same as C = C | 2

    6. Miscellaneous Operator

    Some other operater that are supported by Java are:
    • Conditional Operator/ Ternary Operator: This operator consists of three operands and is used to evaluate Boolean expressions. The goal of the operator is to decide, which value should be assigned to the variable.
      Example:

      variable = (expression) ? value if true : value if false

      public class ConditionalTest {
      
         public static void main(String args[]) {
            int a, b;
            a = 5;
            b = (a == 1) ? 10: 20; // here b will assign to 20, because a==1 is false.
            System.out.println( "Value of b is : " +  b );
         }
      }
    • instanceof Operator: This operator is used only for object reference variables. The operator checks whether the object is of a particular type (class type or interface type).

    Precedence of Java Operators

    Operator precedence determines the grouping of terms in an expression. This affects how an expression is evaluated. Certain operators have higher precedence than others; for example, the multiplication operator has higher precedence than the addition operator −

    For example, x = 7 + 3 * 2; here x is assigned 13, not 20 because operator * has higher precedence than +, so it first gets multiplied with 3 * 2 and then adds into 7.

    Here, operators with the highest precedence appear at the top of the table, those with the lowest appear at the bottom. Within an expression, higher precedence operators will be evaluated first.

    CategoryOperatorAssociativity
    Postfix>() [] . (dot operator)Left toright
    Unary>++ - - ! ~Right to left
    Multiplicative>* /Left to right
    Additive>+ -Left to right
    Shift>>> >>> <<Left to right
    Relational>> >= < <=Left to right
    Equality>== !=Left to right
    Bitwise AND>&Left to right
    Bitwise XOR>^Left to right
    Bitwise OR>|Left to right
    Logical AND>&&Left to right
    Logical OR>||Left to right
    Conditional?:Right to left
    Assignment>= += -= *= /= %= >>= <<= &= ^= |=Right to left

    Syed Masoom Rizvi

    Author & Editor

    Hi, This is Syed Masoom Rizvi, who is continue exploring the world of programming ,programming and programming... :)

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