Computer Science Invitational Test S19D

Computer Science Invitational Test S19D Study Notes

Question 1: Equivalent of 20310

• Choices:

  • A. 3158

  • B. 11010112 (Binary representation)

  • C. CB16 (Hexadecimal representation)

  • D. None.

  • E. More than one.

Question 2: Output of Code Segment

• Code: out.print(14 + -8 * 3 - 12);

• Calculation:

  • First calculate -8 * 3, which equals -24.

  • Then calculate 14 + -24 - 12 = 14 - 24 - 12 = -22.

• Output Choices:

  • A. -22 (Correct)

  • B. 6

  • C. -54

  • D. 26

  • E. -14

Question 3: Output of printf Code Segment

• Code: out.printf("$%10.3f", 789.456123);

• Output Format Explanation:

  • Outputs in a field width of 10; 3 decimal places.

  • Expected output: $789.456. The '#'s represent blank spaces.

• Output Choices:

  • A. $789.456 (Correct)

  • B. $###789.456

  • C. $790

  • D. $##########789.456

Question 4: Output of String Manipulation Code

• Code:

  String sl="serendipity";
  out.print(sl.substring(5, 7) + s1.charAt(4) + s1.charAt(s1.lastIndexOf('e')));

• Analysis:

  • sl.substring(5, 7) equals "di" (substring from index 5 to 6, inclusive).

  • s1.charAt(4) should be verified to see if s1 is defined.

  • s1.charAt(s1.lastIndexOf('e')) returns the character at the last 'e'.

• Output Choices:

  • A. dipne

  • B. ndiee

  • C. dine (Correct)

  • D. din3

  • E. dien

Question 5: Boolean Code Output

• Output Choices:

  • A. true

  • B. false

  • No additional information provided in the context of this question.

Question 6: Compile Status of Lines

• Code:

boolean bl=false, b2=false, b3=false;
out.print(bl && !b2 || b3 ^ true);
long fl=Math.round(2.826); //line 1
int f2=Math.round(3.02); //line 2
double f3=Math.round(5.57f); //line 3
float f4=Math.round(5.46); //line 4

• Analysis:

  • Line 1: Valid

  • Line 2: Invalid (Math.round returns long, cannot assign to int directly)

  • Line 3: Valid

  • Line 4: Valid

• Output Choices:

  • A. line 1

  • B. line 2 (Correct)

  • C. line 3

  • D. line 4

  • E. None of the above. Each line will compile.

Question 7: Code Output for Mathematical Computation

• Output Choices:

  • A. 1.25

  • B. 0.8 (Correct)

  • C. 0.80

  • D. 0

  • E. 1

Question 8: Print Output of Division

• Code:

int i=4,j=5;
out.print(i/j);

• Integer Division:

  • Output is 0 since integer division results in flooring the result.

• Output Choices:

  • A. 23569

Question 9: Printing Entire Alphabet

• Choices:

  • A. Incorrect

  • B. Correct: for (char let='a'; let<='z'; let++) { out.print(let); }

  • C. Incorrect

  • D. Incorrect

  • E. All of the above (Correct)

Question 10: Conclusion of While Loop

• Code Segment:

char chr[] = {'r', 'e', 'u', 'n', 'g'};
int m=0,n=1;
while (chr[m] != 'o') { n = m; m++; }

• Analysis:

  • m will be incremented until it finds 'o', and n stores the index value just before that.

• Output Choices:

  • A. Correct, n stores the index value of the character 'o'.

  • B. m and n are equal.

  • C. n stores the index value of the character 'a'.

  • D. m stores the index value of the character 'a'.

  • E. n and m both store the index value of the character 'o'.

Question 11: Scanner Object Initialization

• Code:

System.out.print(scan.nextInt());
scan.close();

• Choices:

  • A. new Scanner()

  • B. new Scanner(f) (Correct)

  • C. new Scanner("input.dat");

  • D. "input.dat"

  • E. f

Question 12: String Reverse Printing

• Code:

String sl = "";  
String s2 = "mottthehoople";  
for (int i = s2.length() - 1; i >= 0; i --)  
    sl += s2.charAt(i);
    out.print(sl);

• Analysis: Given there is an error in i --.

• Output Choices:

  • A. eoetm

  • B. mteoe

  • C. aloht

  • D. elpoohehtttom

  • E. Throws ArrayIndexOutOfBoundsException.

Question 13: Code Segment Output

• Code Segment:

int x = 8, y = -5, z = 7;  
x = y = z + 10;  
out.print(x + " " + y + " " + z);  

• Expected Output: Needs to evaluate correctly.

• Output Choices:

  • A. 17 17 7

  • B. 20 12 17

  • C. 17 17 17 (Correct)

  • D. 8 -5 17

  • E. 20 17 17

Question 14: Math.max Function Output

• Code:

out.println(Math.max(Short.SIZE, Byte.MAX_VALUE));

• Expected Output:

  • A. 32 (Correct)

  • B. 256

  • C. 16

  • D. 128

  • E. 127