Question 3
Answer:
Question 3
(a) State the number of bytes and bits occupied by a character array of 10 elements.
Answer
As size of char is 2 bytes, a character array of 10 elements occupies 2 x 10 = 20 bytes. 1 byte = 8 bits so 20 bytes convert to 8 x 20 = 160 bits.
(b) Differentiate between Binary Search and Linear Search techniques.
Answer
| Linear Search | Binary Search |
|---|---|
| Linear search works on sorted and unsorted arrays | Binary search works on only sorted arrays (ascending or descending) |
| Each element of the array is checked against the target value until the element is found or end of the array is reached | Array is successively divided into 2 halves and the target element is searched either in the first half or in the second half |
| Linear Search is slower | Binary Search is faster |
(c) What is the output of the following:
String a="Java is programming language \n developed by \t\'James Gosling\'";
System.out.println(a);
Answer
Below is the output of the program:
Java is programming language developed by 'James Gosling'
(d) Differentiate between break and System.exit(0).
Answer
| break | System.exit(0) |
|---|---|
| break statement is used to jump out of the loop or switch-case | System.exit(0) terminates the entire program |
| break is a keyword | System.exit(0) is a method provided by Java standard library |
(e) Write a statement in Java for √((a+b)3÷|a-b|)
Answer
Math.sqrt(Math.pow(a + b, 3) / Math.abs(a - b));
(f) What is the value of m after evaluating the following expression:
m -= 9%++n + ++n/2; when int m=10,n=6
Answer
m = m - (9 % ++n + ++n / 2)
m = 10 - (9 % 7 + 8 / 2)
m = 10 - (2 + 4)
m = 10 - 6
m = 4
(g) Predict output of the following:
(i) Math.pow(25,0.5)+Math.ceil(4.2)
Answer
10.0
Explanation
Math.pow(25,0.5) ⇒ √25 = 5.0
Math.ceil(4.2) = 5.0
5.0 + 5.0 = 10.0
(ii) Math.round ( 14.7 ) + Math.floor ( 7.9)
Answer
22.0
Explanation
Math.round ( 14.7 ) = 15
Math.floor ( 7.9) = 7.0
15 + 7.0 = 22.0
(h) Give the output of the following java statements:
(i) "TRANSPARENT".toLowerCase();
Answer
transparent
(ii) "TRANSPARENT".compareTo("TRANSITION")
Answer
7
Explanation
compareTo method will return the difference in ASCII codes of the first differing characters of both strings. The first differing characters of TRANSPARENT and TRANSITION are P and I, respectively at the 6th position of the strings. Output will be:
ASCII code of 'P' - ASCII code of 'I'
= 80 - 73
= 7
(i) Write a java statement for each to perform the following task:
(i) Find and display the position of the last space in a string str.
Answer
System.out.println(str.lastIndexOf(' '));
(ii) Extract the second character of the string str.
Answer
System.out.println(str.charAt(1));
(j) State the type of errors if any in the following statements:
(i) switch ( n > 2 )
Answer
Syntax Error
Explanation
The expression of switch statement must resolve to byte, short, int, char or String. It cannot resolve to a boolean type so this statement will result in a syntax error.
(ii) System.out.println(100/0);
Answer
Runtime Error
Explanation
The program will compile successfully but when this line is executed it will result in "division by zero" error as dividing any number by 0 is an invalid division operation.
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