Java Operators and Operator precedence questions

Today we are going to practice questions on Java Operators and its precedence. Before you attempt the questions, do a quick review of these two topics by going through our video link here.

1. 1.  Java Operators 
   2. Java Operator Precedence and Associativity

1. Name the type of operators listed below (assignment, relational, logical etc):
   1. <
   2. ++
   3. &&
   4. ?:

   Ans.

   1. Relational Operator
   2. Arithmetic Operator (Increment, unary)
   3. Logical operator (and)
   4. Ternary operator

2. Name the type of operators listed below (assignment, relational, logical etc):

1. 1. !
   2. ==
   3. %
   4. =

Ans.

1. 1.  Logical Operator
   2. Relational Operator
   3. Arithmetic Operator (Modulus)
   4. Assignment operator

3. Operators with higher precedence are evaluated before operators with relatively lower precedence. Arrange the operators given below in order of higher precedence to lower precedence.

(i) &&        (ii) %        (iii) >=         (iv) ++       

Ans. 

(i) ++          (ii)  %            (iii)  >=          (iv)  &&

4. Arrange the operators given below in order of higher precedence to lower precedence.

(i) ()          (ii) ?:         (iii) ==           (iv) | |       

Ans. 

(i) ()            (ii)  ==          (iii)  | |            (iv)  ?:

5. Arrange the operators given below in order of higher precedence to lower precedence.

(i) +         (ii) &&        (iii) !=          (iv) ++ 

Ans. 

(i) ++         (ii) +         (iii)  !=          (iv)  &&

6. What will be the output of the following. if x=5 initially?

(i)  5 * ++x
(ii) 5 * x++

Ans:

(i) 30

(ii) 25

7. What is the result stored in x, after evaluating the following expression?

int x = 5;
x = x++ * 2 + 3 * –x;

Ans.

x=-8

8. Give the output of this code

int a = 9;
a++;
System.out.println (a);
a -= a-- - --a;
System .out.println (a);

Ans:

10
8

Explanation

a = 9;
a++; // a = 10
SOP (a) // Prints 10
a -= a-- - --a;
a = 10 – (10 – 8)
a = 10 -2 = 8
SOP (a) // Prints 8

9. Evaluate the following expression: when a=10, b=8 

i) ++a-b–                   ii) a%b++
iii) a*=b+5               iv) x=69>>>2

Ans

(i) 3                   (ii) 2               (iii)  130                  (iv)  17

10. If m=5 and n=2 output the values of m and n after execution in (i) and (ii).

(i)   m -= n;
(ii)  n = m + m/n;   

Ans:

(i) the value of m is 3 and n is 2
(ii) The value of m is 5 and n is 7

11. What will be the output of the following code?

int k = 5, j = 9;
k += k++ – ++j + k;
System.out.println(“k=” +k);
System.out.println(“j=” +j);

Ans.

k= 6       

j= 10

12. What is the value of y after evaluating the expression given below
    y+=++y + y– + –y; when int y=8.

Ans.

y=33

13. Give the output of the following expression:
    a+=a++ + ++a + –a + a–; when a=7.

Ans.

a=39

14. If int y=10 then find y and z after executing this statement:

int z=(++y * (y++ +5));

Ans.

y=12           z=176

15. What will be the result stored in x after evaluating the following expression?

int x=4;
x += (x++) + (++x) + x;

Ans.

x=20

16. What is the value of y after evaluating the expression given below?
    y += ++y + y– + –y; when int y = 8.

Ans:

y = 8 + 9 + 9 + 7
y = 33

17. What is the value of x1 if x=5 ?

x1=++x – x++ + –x

Ans.

x1= ++x – x++ + –x
x1= 6 (x is incremented to 6) – 6 (x is incremented to 7) + 6 (x is decremented to 6)
= 6

18. Give the output of the following expression :
    a+=a++ + ++a + -–a + a-– ; when a = 7

Ans.

a+=a++ + ++a + –-a + a–- ;
a = 7 + (a++ + ++a + -–a + a–-);
a = 7 + (7 + 9 + 8 + 8);
a = 39

19. If int y = 10 then find int z = (++y * (y++ + 5));

Ans.

Increment operator has the highest precedence. So, ++y and y++ will be evaluated starting from left.

In ++y, the value of y will be incremented to 11 and then 11 will be used in the expression.

When y++ is evaluated, the current value of y i.e. 11 will be used and then y will be incremented from 11 to 12.

int z = (++y * (y++ + 5));
= 11 * (11 + 5 )
= 11 * 16
= 176