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programming languages Online Quiz - 275

Description: programming languages Online Quiz - 275
Number of Questions: 20
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Tags: programming languages
Attempted 0/20 Correct 0 Score 0

Will a C compiler always compile C++ code?

  1. Yes

  2. No

  3. Only optimized compilers will compile C++ code.

  4. None of the Above


Correct Option: B

What does the following code snippet do: for(;;) ;

  1. The snippet is illegal

  2. It loops forever

  3. It is ignored by compiler, but it is not illegal

  4. None of the Above


Correct Option: B

What does the code strcat(an_array, "This"); do?

  1. Copies "This" into an_array

  2. Adds "This" to the end of an_array

  3. Compares an_array and "This"

  4. None of the Above


Correct Option: B
Explanation:

To understand what the code strcat(an_array, "This") does, we need to know that strcat() is a function in C language that concatenates (joins) two strings.

The function takes two arguments: the first argument is the destination array (where the concatenated string will be stored), and the second argument is the source string (which will be concatenated to the destination array).

In this case, the function call strcat(an_array, "This") concatenates the string "This" to the end of the string already stored in an_array. Therefore, the correct option is:

The Answer is: B. Adds "This" to the end of an_array

Evaluate the following: int fn(int v) { if(v==1 || v==0) return 1; if(v%2==0) return fn(v/2)+2; else return fn(v-1)+3; } for fn(7);

  1. 10

  2. 11

  3. 1

  4. None of the Above


Correct Option: B

Which of the following is not a valid keyword:

  1. public

  2. protected

  3. guarded

  4. None of the Above


Correct Option: C

What is the correct syntax for inheritance?

  1. class aclass : public superclass

  2. class aclass inherit superclass

  3. class aclass

  4. None of the Above


Correct Option: A

AI Explanation

To answer this question, you need to understand the syntax for inheritance in programming languages.

Inheritance is a concept in object-oriented programming that allows one class to inherit properties and methods from another class. In most programming languages, including C++, the correct syntax for inheritance is:

A) class aclass : public superclass

This option is correct because it follows the standard syntax for inheritance. The "class aclass" statement declares a new class called "aclass", and the ": public superclass" part indicates that "aclass" inherits from the "superclass".

Option B) class aclass inherit superclass - This option is incorrect because it does not use the correct syntax for inheritance. The keyword "inherit" is not used to indicate inheritance in most programming languages.

Option C) class aclass

Of the numbers 12, 23, 9, and 28, which one would be at the top of a properly implemented maxheap?

  1. 28

  2. 9

  3. Any of them could be

  4. None of the Above


Correct Option: A

What does the line containing "break;" do in the following code? void afunction() { if(1) { break; a_function(); cout<

  1. Breaks out of the if statement

  2. Exits the function

  3. Nothing (Compiler error)

  4. None of the Above


Correct Option: C

If you push 1, 3, and 5 - in that order - onto a stack, which number is popped out first?

  1. 5

  2. 1

  3. 3

  4. None of the Above


Correct Option: A

Which of the following data structures is on average the fastest for retrieving data:

  1. Binary Tree

  2. Hash Table

  3. Stack

  4. None of the Above


Correct Option: B

Which is not valid in C?

  1. class aClass{public:int x;};

  2. /* A comment */

  3. char x=12;

  4. None of the Above


Correct Option: A

Which of the following is not a valid declaration for main()?

  1. int main()

  2. int main(int argc, char *argv[])

  3. They both work

  4. None of the Above


Correct Option: C

Evaluate the following as true or false: !(1 &&0 || !1)

  1. True

  2. False

  3. Invalid Statement

  4. None of the Above


Correct Option: A

Which command properly allocates memory?

  1. char *a=new char[20];

  2. char a=new char[20];

  3. char a=new char(20.0);

  4. None of the Above


Correct Option: A

Would you rather wait for the results of a quicksort, a linear search, or a bubble sort on a 200000 element array?

  1. Quicksort

  2. Linear Search

  3. Bubble Sort

  4. none of the above


Correct Option: B

Q: 1 Given: 11. public class Person { 12. private String name, comment; 13. private int age; 14. public Person(String n, int a, String c) { 15. name = n; age = a; comment = c; 16. } 17. public boolean equals(Object o) { 18. if (! (o instanceof Person)) return false; 19, Person p = (Person)o; 20. return age == p.age && name.equals(p.name); 21. } 22. } What is the appropriate definition of the hashCode method in class Person?

  1. A. return super.hashCode();

  2. B. return name.hashCode() + age * 7;

  3. C. return name.hashCode() + comment.hashCode() / 2;

  4. D. return name.hashCode() + comment.hashCode() / 2 - age * 3;


Correct Option: A

2 Given: 34. HashMap props = new HashMap(); 35. props.put("key45", "some value"); 36. props.put("key12", "some other value"); 37. props.put("key39", "yet another value"); 38. Set s = props.keySet(); 39. // insert code here What, inserted at line 39, will sort the keys in the props HashMap?

  1. A. Arrays.sort(s);

  2. B. s = new TreeSet(s);

  3. C. Collections.sort(s);

  4. D. s = new SortedSet(s);


Correct Option: B
Explanation:

To sort the keys in the props HashMap, the user needs to know about the different data structures available in Java that can help to sort a collection of keys. The user also needs to know about the methods provided by the Java Collections framework that can be used to perform sorting on collections.

Option A: Arrays.sort(s); is incorrect. The Arrays.sort() method is used to sort arrays, not sets or maps. It will result in a compilation error.

Option B: s = new TreeSet(s); is correct. A TreeSet is a sorted set that orders its elements based on their natural ordering or based on a comparator provided at the time of creation. By creating a new TreeSet using the Set of keys from the props HashMap, the keys will be automatically sorted.

Option C: Collections.sort(s); is incorrect. The Collections.sort() method is used to sort lists, not sets or maps. It will result in a compilation error.

Option D: s = new SortedSet(s); is incorrect. SortedSet is an interface and cannot be instantiated. Moreover, the Set obtained from the props HashMap is already sorted.

Therefore, the correct answer is:

The Answer is: B. s = new TreeSet(s);

for (printf("a");printf("b");printf("c")) { break; } What will be the output of the above code snippet?

  1. ab

  2. abc

  3. c

  4. none of the above


Correct Option: A

i=3; Printf("%d%d%d",i++,++i,i); What will be output of the code snippet?

  1. 345

  2. 456

  3. 344

  4. 443


Correct Option: D
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