Module 5 Assignment 3.3 Answer

3.3 Grade Calculation Based on Score

Question

Write a Python program that:

• Prompts the user to enter a score between 0.0 and 1.0.
• If the score is out of range, print "Error: Invalid score" and exit.
• If the score is valid, print the corresponding grade based on the table below:

Test Case: Enter 0.85, the expected output should be B.

Correct Python Code

# Prompt user for input
score = input("Enter Score: ")

try:
    # Convert input to float
    score = float(score)

    # Check if the score is within valid range
    if score < 0.0 or score > 1.0:
        print("Error: Invalid score")
    else:
        # Determine the grade based on score
        if score >= 0.9:
            print("A")
        elif score >= 0.8:
            print("B")
        elif score >= 0.7:
            print("C")
        elif score >= 0.6:
            print("D")
        else:
            print("F")

except ValueError:
    # Handle non-numeric input
    print("Error: Invalid input")

Expected Output

Enter Score: 0.85
B

Explanation

1. Prompt the user to enter a score.
2. Convert input to float (handle errors using try/except).
3. Check if the score is in range (0.0 to 1.0), else print "Error: Invalid score".
4. Determine the grade using if-elif conditions.
5. Handle non-numeric inputs using try/except to avoid program crashes.

Why This Code is Correct

✅ Ensures valid input (between 0.0 and 1.0).
✅ Handles non-numeric inputs gracefully.
✅ Uses proper conditional logic for grading.
✅ Produces expected output when tested with 0.85 → B.