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. Input Validation Function (ReadNumberInRange)

• Uses a do-while loop to repeatedly prompt the user for a grade.
• Ensures the input is between 0 and 100 (inclusive).
• Returns the validated grade.

3. Grade Conversion Function (GetGradeLetter)

• Takes a numeric grade as input.
• Determines the corresponding letter grade based on the following ranges:
  • 90+ → 'A'
  • 80-89 → 'B'
  • 70-79 → 'C'
  • 60-69 → 'D'
  • 50-59 → 'E'
  • Below 50 → 'F'
• Returns the computed letter grade.

4. Program Execution (main())

• Calls ReadNumberInRange(0, 100) to get user input.
• Calls GetGradeLetter() to determine the letter grade.
• Prints the result.
• Returns 0 to indicate successful execution.

This structured explanation ensures clarity and ease of understanding.