Test: Arrays - 2 - EmSAT Achieve MCQ

In C++, the index of the first element in an array is always 0.

The maximum number of elements an array can hold in C++ depends on various factors such as the implementation, system limitations, and available memory.

The index of the nth element in an array is (n-1), as array indices start from 0 in C++.

Multi-dimensional arrays in C++ are represented as a linear sequence of elements in memory. They can have different sizes for each dimension.

Uninitialized elements in an array have undefined values and can contain garbage values.

Arrays in C++ have a fixed size once declared. Their size cannot be changed dynamically during runtime.

Elements in a 2D array are stored in a column-wise manner. The elements of each column are stored adjacent to each other in memory.

The size of an array in bytes depends on the data type of the elements and the number of elements in the array. It can be calculated using the formula sizeof(array).

The code declares an integer array 'arr' with 5 elements and initializes them with values 1, 2, 3, 4, and 5. The statement 'cout << arr[3] << endl;' prints the value at index 3, which is 4.

The code declares an integer array 'arr' with 5 elements and initializes them with values 1, 2, 3, 4, and 5. The statement 'cout << arr[10] << endl;' tries to access an element at index 10, which is beyond the array's size. It will result in undefined behavior and may print a garbage value.

The code declares an integer array 'arr' with 5 elements but does not initialize them. In C++, uninitialized elements in an array are set to 0 by default. The statement 'cout << arr[0] << endl;' prints the value at index 0, which is 0.

The code declares an integer array 'arr' with 5 elements and initializes the first three elements with values 1, 2, and 3. The remaining two elements are not explicitly initialized and will contain garbage values. The statement 'cout << arr[4] << endl;' prints the value at index 4, which may be a garbage value.

The code declares an integer array 'arr' with 5 elements and prints the value of 'arr'. In C++, when an array name is used in an expression, it decays into a pointer to its first element. Therefore, 'cout << arr << endl;' prints the memory address of the first element in the array.

The code declares an integer array 'arr' with 5 elements. The 'sizeof(arr)' returns the size of the entire array in bytes, which is equal to the number of elements (5) multiplied by the size of each element (4 bytes for an integer). Therefore, 'cout << sizeof(arr) << endl;' prints 20.

The code declares an integer array 'arr' with 5 elements. The 'sizeof(arr)' returns the size of the entire array in bytes, and 'sizeof(arr[0])' returns the size of each element in bytes. Therefore, 'cout << sizeof(arr) / sizeof(arr[0]) << endl;' prints the number of elements in the array, which is 5.

Bubble Sort has a worst-case time complexity of O(n^2) when the array is reverse sorted. It involves repeatedly swapping adjacent elements if they are in the wrong order.

Merge Sort can be implemented using a recursive approach. It divides the array into two halves, recursively sorts them, and then merges the sorted halves.

The code implements the Bubble Sort algorithm to sort the array 'arr' in ascending order. After sorting, the value at index 3 will be 3. Therefore, 'cout << arr[3] << endl;' prints 3.

Merge Sort has an average-case time complexity of O(n log n), which is the best among the given sorting algorithms. It recursively divides the array into halves and merges them in a sorted manner.

Insertion Sort is known for its simplicity and suitability for small input sizes. It works by gradually building a sorted portion of the array and inserting elements in the correct order.