Solution Source Code:

Code Overview

1. Header Files and Namespace:

• <iostream> is included for input and output operations.
• <string> is included for potential future use (not used in this program).
• using namespace std; allows the use of standard functions without prefixing them with std::.

2. User Input Function (ReadNumbers)

• Uses reference parameters (int &Mark1, int &Mark2, int &Mark3) to modify the values directly.
• Prompts the user to enter three exam marks and stores them in the provided reference variables.

3. Sum Calculation Function (SumOf3Marks)

• Takes three integer values as input.
• Returns the sum of the three marks.

4. Average Calculation Function (CalculateAverage)

• Calls SumOf3Marks() to compute the total sum.
• Divides the sum by 3 to calculate the average.
• Returns the computed average as a float.

5. Output Function (PrintResults)

• Receives the calculated average as a parameter.
• Prints "The average is: [Average]".

6. Program Execution (main())

• Declares three integer variables (Mark1, Mark2, Mark3).
• Calls ReadNumbers() to get user input.
• Calls CalculateAverage() to compute the average.
• Calls PrintResults() to display the average.
• Returns 0 to indicate successful execution.

This structured explanation ensures clarity and ease of understanding.