Multiple Choice Questions

Question 1

The statement n += 4 is equivalent to:

1. ++n

2. n=n+4

3. n+1

4. none

Question 2

What will be the output of a & b in the following, if int a, b; a=10; b=a++;

1. 10,10

2. 10,11

3. 11,10

4. 11,11

Question 3

What will be the output of a++ when int a = -1;

1. 1

2. -1

3. 0

4. none

Question 4

If int a = 25, b = 5, c = 0; what value is stored in c? When c = a % b;

1. 5.0

2. 5

3. 0

4. none

Question 5

What is the result of the following in Java statement?

int m=8;

m*=8;

System.out.println("The output =" + m);

1. 8

2. 64

3. 16

4. 88

Question 6

double c;

int x, y, z;

x = 5; y = 10; z = 11;

c = x*y+z/2;

The value stored in c is:

1. 55.0

2. 55.5

3. 55

4. none

Explanation

c = x * y + z / 2

⇒ c = 5 * 10 + 11 / 2

⇒ c = 5 * 10 + 5

⇒ c = 50 + 5

⇒ c = 55.0

Question 7

int m, p;

m = 5;

p = 0;

p = m-- + --m;

The output will be:

1. 11

2. 10

3. 8

4. 12

Explanation

p = m-- + --m;

⇒ p = 5 + 3

⇒ p = 8

Question 8

int a=7, p=0, q=0;

p= ++a + --a;

q -= p;

The output of q will be:

1. 13

2. 14

3. 15

4. -15

Explanation

p = ++a + --a

⇒ p = 8 + 7

⇒ p = 15

q -= p

⇒ q = q - p

⇒ q = 0 - 15

⇒ q = -15

Write the Java expressions for the following:

Question 1

p = a² + bc

Answer

p = a * a + b * c

Question 2

m = a² - b² / (ab)

Answer

m = (a * a - b * b) / (a * b)

Question 3

s = ut + (1/2)at²

Answer

s = u * t + (1 / 2) * a * t * t

Question 4

f = uv / (u + v)

Answer

f = u * v / (u + v)

Question 5

(a + b)² + b

Answer

(a + b) * (a + b) + b

Question 6

y = 2(lb + bh + lh)

Answer

y = 2 * (l * b + b * h + l * h)

Question 7

a² + b²

Answer

a * a + b * b

Question 8

z = x³ + y³ - xy / 3

Answer

z = x * x * x + y * y * y - x * y / 3

Answer the following questions

Question 1

What is an operator?

An operator is a symbol or sign used to specify an operation to be performed in Java programming.

Question 2

Name the different types of operators.

The different types of operators are Arithmetical, Logical and Relational.

Question 3

Explain the following:

(a) Arithmetical operator

Arithmetic operators are used to perform mathematical operations on its operands. Operands of arithmetic operators must be of numeric type. A few arithmetic operators operate upon one operand. They are called Unary Arithmetic operators. Other arithmetic operators operate upon two operands. They are called Binary Arithmetic operators. As an example consider the below statement:

int a = 10 + 20;

Here, the addition arithmetic operator, represented by the symbol + will add 10 and 20. So variable a will be 30.

(b) Relational operator

Relational operators are used to determine the relationship between the operands. Relational operators compare their operands to check if the operands are equal to ( == ), not equal to ( != ), less than ( < ), less than equal to ( <= ), greater than ( > ), greater than equal to ( >= ) each other. The result of an operation involving relation operators is a boolean value — true or false.

Example:

int a = 8;

int b = 10;

boolean c = a < b;

Here, as a is less than b so the result of a < b is true. Hence, boolean variable c becomes true.

(c) Logical operator

Logical operators operate on boolean expressions to combine the results of these boolean expression into a single boolean value.

Example:

int a = 7;

int b = 10;

boolean c = a < b && a % 2 == 0;

Here, the result of first boolean expression a < b is true and the result of second boolean expression a % 2 is false. The logical AND operator ( && ) combines these true and false boolean values and gives a resultant boolean value as false. So, boolean variable c becomes false.

(d) Unary operator

Operators that act on one operand are called as Unary operators. Unary +, unary -, ++, --, etc. are some unary operators in Java.

(e) New operator

new operator is used to instantiate an object by dynamically allocating memory for it.

(f) Binary operator

Operators that act on two operands are called as Binary operators.

Question 4

What is a Ternary operator? Explain with the help of an example.

condition ? expression 1 : expression 2

Ternary operator evaluates the condition. If the condition is true then result of ternary operator is the value of expression 1. Otherwise the result is the value of expression 2.

Example:

boolean isLeapYear = true;

int febDays = isLeapYear ? 29 : 28;

Here, the ternary operator checks if the value of boolean variable isLeapYear is true or false. As it is true, expression 1, which in this example is the value 29, is the result of the ternary operator. So, int variable

5.(e) System.out.print( ) and System.out.println( )

System.out.print( )

• It prints data to the console but the cursor remains at the end of the data in the same line.

• Next printing takes place from the same line.

System.out.println( )

• It prints data to the console and places the cursor in the next line.

• Next printing takes place from next line.

Question 6

Differentiate between an operator and an expression.

An operator is a symbol or sign used to specify an operation to be performed whereas an expression is a set of variables, constants and operators i.e. an expression is a combination of operators and operands.

Question 7

If m=5 and n=2 then what will be the output of m and n after execution that will store in (a) & (b)?

(a) m -= n;

Answer

m -= n

⇒ m = m - n

⇒ m = 5 - 2

⇒ m = 3

(b) n = m + m/n;

Answer

n = m + m/n

⇒ n = 5 + 5 / 2

⇒ n = 5 + 2

⇒ n = 7

Question 8

State the difference between = and ==.

=

==

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 9

What will be the output for the following program segment?

int a=0,b=10,c=40;

a = --b + c++ +b;

System.out.println(" a = " + a);

Output

a = 58

Explanation

a = --b + c++ + b

⇒ a = 9 + 40 + 9

⇒ a = 58

Question 10

What will be the output of the following?

if x =5

(a) 5* ++x;

Answer

5 * ++x

⇒ 5 * 6

⇒ 30

(b) 5* x++;

Answer

5 * x++

⇒ 5 * 5

⇒ 25

Question 11

Evaluate the following expressions, if the values of the variables are:

a = 2, b = 3, and c = 9

(a) a - (b++) * (--c);

Answer

a - (b++) * (--c)

⇒ 2 - 3 * 8

⇒ 2 - 3 * 8

⇒ 2 - 24

⇒ -22

(b) a * (++b) % c;

Answer

a * (++b) % c

⇒ a * (++b) % c

⇒ 2 * (4) % 9

⇒ 8 % 9

⇒ 8

Question 12

If a = 5, b = 9, calculate the value of:

a += a++ - ++b + a;

Answer

a += a++ - ++b + a

⇒ a = a + (a++ - ++b + a)

⇒ a = 5 + (5 - 10 + 6)

⇒ a = 5 + 1

⇒ a = 6

Question 13

Give the output of the program snippet.

int a = 10, b =12;

if(a>=10)

a++;

else

++b;

System.out.println(" a = " + a + " and b = " +b);

Output

a = 11 and b = 12

Explanation

The condition if(a>=10) is true so a++ increments a to 11. b remains the same.

Question 14

Rewrite the following using ternary operator.

if(income<=100000)

tax = 0;

else

tax = (0.1*income);

Answer

tax = income <= 100000 ? 0 : (0.1*income);

Question 15

Rewrite the following using ternary operator.

if(p>5000)

d = p*5/100;

else

d = 2*p/10;

Answer

d = p > 5000 ? p * 5 / 100 : 2 * p / 10;