Question 1

Question 1What are logical operators? Give an example of each.

Accepted Answer

Logical operators operate only on boolean operands and are used to construct complex decision-making expressions. Some of the logical operators are given below:OperatorSymbolLogical AND&&Logical OR||Logical NOT!

Question 2

Question 2What is an assignment operator? Give an example.

Accepted Answer

Assignment operator is used to assign the value of an expression to a variable. It has the following syntax:variable = expression;For example,totalMarks = 780;The above statement assigns the value of 780 to the variable totalMarks. Any previous value stored in totalMarks variable is overwritten by this new value.

Question 3

Question 3Explain the shorthand assignment operator with an example.

Accepted Answer

Java provides shorthand assignment operators for all the arithmetic binary operators. Shorthand assignment operators follow the below syntax:variable = variable operation expression;Taking the example of shorthand addition operator, the expression x = x + 3 can be rewritten as x += 3;

Question 4

Question 4What is the use and syntax of a ternary operator?

Accepted Answer

Ternary operator is used to check if a condition is true and false. Depending on whether the condition tests true or false, expression 1 or expression 2 is evaluated. Its syntax is:boolean-expression ? expression1 : expression2;

Question 5

Question 5State the difference between = and ==.

Accepted Answer

===It is the assignment operator used for assigning a value to a variable.It is the equality operator used to check if a variable is equal to another variable or literal.E.g. int a = 10; assigns 10 to variable a.E.g. if (a == 10) checks if variable a is equal to 10 or not.

Question 6

Question 6If a = 5, b = 9, calculate the value of:    a += a++ - ++b + a

Accepted Answer

a += a++ - ++b + a⇒ a = a + (a++ - ++b + a)⇒ a = 5 + (5 - 10 + 6)⇒ a = 5 + 1⇒ a = 6a++ first uses the current value of a (which is 5) in the expression and then increments it to 6. ++b first increment the current value of b to 10 and uses this incremented value in the expression.

Question 7

Question 7If x = 3, y = 7, calculate the value of:x -= x++ - ++y

Accepted Answer

x -= x++ - ++y⇒ x = x - (x++ - ++y)⇒ x = 3 - (3 - 8)⇒ x = 3 - (-5)⇒ x = 3 + 5⇒ x = 8

Question 8

Question 8What will be the output of the following if x=5?i. 5 * ++xii. 5 * x++

Accepted Answer

i.  5 * ++x⇒ 5 * 6⇒ 30ii.  5 * x++⇒ 5 * 5⇒ 25

Question 9

Question 9What is type conversion? How is an implicit type conversion different from explicit type conversion?

Accepted Answer

Type conversion is a process that converts a value of one data type to another data type.In an implicit conversion, the result of a mixed mode expression is obtained in the higher most data type of the variables without any intervention by the user. For example:int a = 10;
float b = 25.5f, c;
c = a + b;In case of explicit type conversion, the data gets converted to a type as specified by the programmer. For example:int a = 10;
double b = 25.5;
float c = (float)(a + b);

Question 10

Question 10What do you understand by type conversion?

Accepted Answer

Type conversion is a process that converts a value of one data type to another data type.

Question 11

Question 11What is typecasting in Java? Give an example.

Accepted Answer

The process of converting a value of one data type to another data type is called typecasting. For example:int a = 10;
double b = 25.5;
float c = (float)(a + b);

Question 12

Question 12What are precedence and associativity?

Accepted Answer

Precedence of operators refers to the order in which the operators are applied to the operands in an expression.Associativity of operators refers to the direction of execution of operators ("Left to Right" or "Right to Left") when operators in an expression have the same precedence.

Question 13

Question 13Evaluate the following expressions, if the values of the variables are a = 2, b = 3 and c = 3i. a - (b++) * (--c)ii. a * (++b) %c

Accepted Answer

i.  a - (b++) * (--c)⇒ 2 - 3 * 2⇒ 2 - 6⇒ -4ii. a * (++b) %c⇒ 2 * 4 % 3⇒ 8 % 3⇒ 2

Question 14

Question 14Write the Java expressions for the following:i. (a + b)2 + b

Accepted Answer

Math.pow(a+b, 2) + bii. a2 + b2a * a + b * biii. z = x3 + y3 + (xy) / 3z = Math.pow(x, 3) + Math.pow(y, 3) + x * y / 3iv. f = a2 + b2 / a2 - b2f = (a * a + b * b) / (a * a - b * b)v. z = ab + bc + ca / 3abcz = (a * b + b * c + c * a) / (3 * a * b * c)vi. 0 <= x <= 50x >= 0 && x <= 50

Question 15

Question 15Rewrite the following statements without using shorthand operators.a. p /= qb. p -= 1c. p *= q + rd. p -= q - r

Accepted Answer

a. p = p / qb. p = p - 1c. p = p * (q + r)d. p = p - (q - r)

Question 16

Question 16Determine the output of the following program.public class Test
{
    public static void main(String[] args) 
    {
        int a = 1, b = 2;
        System.out.println("Output1: " + a + b);
        System.out.println("Output2: " + (a + b));
    }
}

Accepted Answer

Please refer to the full solution above.

Question 17

Question 17What is the difference between the following two statements? Explain the results.x -= 5;x =- 5;

Accepted Answer

The first statement, x -= 5; subtracts 5 from x and assigns the result back to x. It is equivalent to x = x - 5;The second statement, x =- 5; assigns the value of -5 to x.

Question 18

Question 18What is concatenation? On which data type is concatenation performed?

Accepted Answer

Concatenation means joining two strings together. It is performed on String data type.

Question 19

Question 19Determine the output of the following program.public class PredictOutput1
{
  public static void main(String args[])
  {
       int a = 4, b = 2, c = 3;
       System.out.println("Output 1: " + (a = b * c));
       System.out.println("Output 2: " + (a = (b * c)));
  }
}

Accepted Answer

Please refer to the full solution above.

Question 20

Question 20Determine the output of the following program.public class PredictOutput2
{
  public static void main(String args[])
  {
       int a = 6, b = 2, c = 3;
       System.out.println("Output 1: " + (a == b * c)); 
       System.out.println("Output 2: " + (a == (b * c)));
  }
}

Accepted Answer

Please refer to the full solution above.

Operators in Java