Chapter 5: MCQs on Arrays and Strings in C++ | C++ Programming

Master Arrays and Strings in C++ | 30 Key MCQs for Comprehensive Learning

Understanding arrays and strings is crucial for any C++ programmer. These 30 MCQs cover the fundamentals of single and multi-dimensional arrays, strings, and essential string manipulation functions like strlen, strcpy, and strcat.

MCQs

1-6: Introduction to Arrays

1. An array is a collection of:
   • A) Variables of different data types
   • B) Functions
   • C) Variables of the same data type
   • D) Constants
2. What is the starting index of an array in C++?
   • A) -1
   • B) 0
   • C) 1
   • D) Depends on the compiler
3. Which of the following best describes an array?
   • A) A data structure that can store elements sequentially
   • B) A list of unrelated variables
   • C) A file storage system
   • D) A single variable with a fixed value
4. The syntax for declaring an array of 10 integers in C++ is:
   • A) int arr[10];
   • B) int arr;
   • C) int arr[10][10];
   • D) int[10] arr;
5. How do you access the third element of an array named myArray?
   • A) myArray(2);
   • B) myArray[3];
   • C) myArray[2];
   • D) myArray{3};
6. What happens if you try to access an array index that is out of bounds in C++?
   • A) The program crashes
   • B) Random data is accessed
   • C) Compile-time error
   • D) Undefined behavior

7-12: Single-Dimensional Arrays

7. Which of the following statements about single-dimensional arrays is correct?
   • A) They can store elements of different data types
   • B) They store elements in a sequential manner
   • C) They require the class keyword
   • D) They are dynamic by default
8. How can you initialize an array in C++ with specific values?
   • A) int arr = {1, 2, 3};
   • B) int arr[] = {1, 2, 3};
   • C) arr[3] = int {1, 2, 3};
   • D) array int arr = {1, 2, 3};
9. What will be the output if the following array is initialized as int arr[5] = {1, 2};?
   • A) Only 1 and 2 are stored; the rest are undefined
   • B) All elements are zero
   • C) First two elements are 1 and 2, rest are 0
   • D) Error due to incomplete initialization
10. Which of the following operations cannot be performed directly on a single-dimensional array?
    • A) Inserting an element
    • B) Modifying an element
    • C) Accessing an element
    • D) Deleting an element
11. If an array has 7 elements, what is the index of the last element?
    • A) 6
    • B) 7
    • C) 5
    • D) Cannot be determined
12. Which function can you use to find the size of an array in C++?
    • A) sizeof
    • B) strlen
    • C) sizeof() / sizeof(array[0])
    • D) Both A and C

13-18: Multi-Dimensional Arrays

13. What is a multi-dimensional array?
    • A) An array containing elements of different data types
    • B) An array of arrays
    • C) An array with a single row
    • D) A dynamic array
14. How do you declare a 2D array with 3 rows and 4 columns in C++?
    • A) int arr[4][3];
    • B) int arr[3,4];
    • C) int arr[3][4];
    • D) int arr[3x4];
15. How do you access the element in the second row and third column of a 2D array named matrix?
    • A) matrix[1][2];
    • B) matrix[2][3];
    • C) matrix[3][2];
    • D) matrix[2][1];
16. Which of the following statements is true about multi-dimensional arrays?
    • A) They only allow integer values
    • B) They are arrays within arrays
    • C) They always require a pointer
    • D) They are dynamic in nature
17. If a 2D array arr has dimensions [3][3], how many elements can it hold?
    • A) 3
    • B) 6
    • C) 9
    • D) 12
18. What happens if you try to access an element outside the range of a 2D array?
    • A) Syntax error
    • B) Undefined behavior
    • C) Compiler warning
    • D) Default value returned

19-24: Introduction to Strings in C++

19. In C++, strings are:
    • A) A data type for numeric operations
    • B) Arrays of characters
    • C) Always defined using char
    • D) None of the above
20. What is the difference between char str[] = "Hello"; and char *str = "Hello";?
    • A) str[] is mutable; *str is a pointer to a constant
    • B) str[] is immutable; *str is mutable
    • C) str[] requires a pointer
    • D) Both are identical
21. What is the default value of an uninitialized string in C++?
    • A) 0
    • B) null
    • C) Empty string
    • D) Undefined
22. Which of the following is NOT a way to initialize a C++ string?
    • A) std::string str("Hello");
    • B) std::string str = "Hello";
    • C) std::string str;
    • D) string str = "Hello";
23. Which function can be used to concatenate two C++ strings?
    • A) strcat
    • B) strjoin
    • C) concat
    • D) join
24. In C++, a string is terminated by:
    • A) Null character '\0'
    • B) Space character ' '
    • C) Newline '\n'
    • D) None of the above

25-30: String Manipulation Functions (strlen, strcpy, strcat)

25. The function strlen in C++ is used to:
    • A) Concatenate strings
    • B) Calculate the length of a string
    • C) Copy one string to another
    • D) Compare two strings
26. What does strcpy do in C++?
    • A) Copies one string to another
    • B) Finds the length of a string
    • C) Concatenates two strings
    • D) None of the above
27. Which header file is required to use strlen, strcpy, and strcat?
    • A) <cmath>
    • B) <iostream>
    • C) <cstring>
    • D) <cstdlib>
28. What does strcat do?
    • A) Copies one string to another
    • B) Appends one string to another
    • C) Finds the length of a string
    • D) Splits a string
29. If char str1[20] = "Hello"; and char str2[20] = "World";, what does strcat(str1, str2); do?
    • A) Hello
    • B) WorldHello
    • C) HelloWorld
    • D) Hello World
30. What will strlen("Hello World"); return?
    • A) 11
    • B) 10
    • C) 12
    • D) 9

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