What You'll Learn
- •Using if-elif-else chains for ranges
- •Validating numeric input
- •Mapping continuous values to categories
Python
# Program to calculate grade from percentage
percentage = float(input("Enter your percentage: "))
if percentage < 0 or percentage > 100:
print("Invalid percentage. Please enter a value between 0 and 100.")
else:
if percentage >= 90:
grade = 'A'
elif percentage >= 80:
grade = 'B'
elif percentage >= 70:
grade = 'C'
elif percentage >= 60:
grade = 'D'
else:
grade = 'F'
print(f"Your grade is: {grade}")Output
Enter your percentage: 85 Your grade is: B
We map a numeric percentage to a letter grade using an if-elif-else ladder:
- 90–100 → A
- 80–89 → B
- 70–79 → C
- 60–69 → D
- Below 60 → F
We also validate that the percentage is between 0 and 100 before grading.
Step-by-Step Breakdown
- 1Read percentage from the user.
- 2Check that it lies between 0 and 100.
- 3Use if-elif-else to assign a letter grade.
- 4Print the resulting grade.