Array indexing and access in C Sharp (C#) - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this array access code?

Consider the following C# code snippet. What will be printed to the console?

C Sharp (C#)

int[] numbers = {10, 20, 30, 40, 50};
Console.WriteLine(numbers[2]);

A 20

B 10

C 30

D 40

💡 Hint

Remember, array indexing in C# starts at 0.

The array numbers has elements indexed from 0 to 4. The element at index 2 is the third element, which is 30.

❓ Predict Output

intermediate

What happens when accessing an invalid array index?

What will happen when this code runs?

C Sharp (C#)

int[] values = {1, 2, 3};
Console.WriteLine(values[3]);

A Prints 3

B Throws IndexOutOfRangeException

C Prints 0

D Prints null

💡 Hint

Check what happens if you try to access an index outside the array bounds.

Arrays in C# have fixed size. Accessing index 3 in an array of size 3 (indices 0,1,2) causes an IndexOutOfRangeException.

❓ Predict Output

advanced

What is the output of this multidimensional array access?

Given the code below, what will be printed?

C Sharp (C#)

int[,] matrix = { {1, 2}, {3, 4} };
Console.WriteLine(matrix[1, 0]);

A 3

B 2

C 1

D 4

💡 Hint

Remember the first index is the row, the second is the column.

The element at row 1, column 0 is 3.

❓ Predict Output

advanced

What is the output of this jagged array access?

What will this code print?

C Sharp (C#)

int[][] jagged = new int[][] {
    new int[] {1, 2},
    new int[] {3, 4, 5}
};
Console.WriteLine(jagged[1][2]);

A 5

B 3

C 4

D 2

💡 Hint

Jagged arrays are arrays of arrays. Access the second array, then its third element.

The second array is {3,4,5}. The element at index 2 is 5.

❓ Predict Output

expert

What is the output of this code with negative indexing attempt?

What will happen when this code runs?

C Sharp (C#)

int[] arr = {100, 200, 300};
Console.WriteLine(arr[-1]);

A Prints 300

B Prints -1

C Prints 100

D Throws IndexOutOfRangeException

💡 Hint

Check if C# supports negative indexes for arrays.

C# arrays do not support negative indexing. Accessing arr[-1] throws IndexOutOfRangeException.