6.3. Preview Questions#
Complete these questions before class to prepare for the chapter. Use the dropdowns to check your answers.
6.3.1. True or False#
1. Arrays in C# have a fixed size once created.
Answer
True — Array size is set at creation; use List<T> for dynamic sizing.
2. The first element of a C# array is at index 1.
Answer
False — C# arrays are zero-indexed; the first element is at index 0.
3. A jagged array in C# can have different numbers of columns per row.
Answer
True — Jagged arrays (int[][]) allow rows of different lengths.
4. array.Length returns the total number of elements in a 1D array.
Answer
True — Length gives the total element count.
5. You can store mixed data types (e.g., int and string) in a single typed array.
Answer
False — A typed array is homogeneous; use object[] for mixed types.
6.3.2. Multiple Choice#
1. How do you declare an integer array of 5 elements in C#?
a) int array[5]
b) int[] array = new int[5]
c) array int[5]
d) int array = new[5]
Answer
b) int[] array = new int[5] — C# uses int[] for the type and new int[5] to allocate.
2. What index accesses the last element of an array with 8 elements?
a) arr[8]
b) arr[7]
c) arr[-1]
d) arr[9]
Answer
b) arr[7] — Last index = Length - 1 = 7.
3. Which loop construct is most natural for iterating all array elements?
a) while
b) do-while
c) foreach
d) goto
Answer
c) foreach — foreach iterates elements without managing an index variable.
4. In int[,] grid = new int[3, 4], how many elements does the grid hold?
a) 7
b) 3
c) 4
d) 12
Answer
d) 12 — 3 rows × 4 columns = 12 elements.
5. What happens when you access an array index outside its bounds?
a) Returns 0
b) Returns null
c) Throws IndexOutOfRangeException
d) Wraps around to the other end
Answer
c) Throws IndexOutOfRangeException — Out-of-bounds access throws IndexOutOfRangeException at runtime.
Footnotes