Write a program that asks for the number of calories and fat grams in a food. The program should display the percentage
of calories that come from fat
One gram of fat has 9 calories, so Calories from fat = fat grams * 9
The percentage of calories from fat can be calculated as: calories from fat/total calories
Input validation: Make sure the number of calories and fat grams are not less than 0.
Also, the number of calories from fat cannot be greater than the total number of calories. If that happens, display an
error message indicating that either the calories or fat grams were incorrectly entered.
Here is a Python program that calculates the percentage of calories that come from fat based on the number of calories and fat grams entered:
```python
# Prompt for user input
calories = float(input("Enter the number of calories in the food: "))
fat_grams = float(input("Enter the number of fat grams in the food: "))
# Input validation
if calories < 0 or fat_grams < 0:
print("Error: The number of calories and fat grams cannot be less than 0.")
elif fat_grams * 9 > calories:
print("Error: The calories from fat cannot be greater than the total number of calories.")
else:
# Calculate calories from fat and percentage of calories from fat
calories_from_fat = fat_grams * 9
percentage_of_calories_from_fat = (calories_from_fat / calories) * 100
# Display the result
print(f"The percentage of calories that come from fat is: {round(percentage_of_calories_from_fat, 2)}%")
```
To execute this program, you can either run it in a Python IDE or save the code in a Python file (e.g., `calories_from_fat.py`) and run the file using the Python interpreter.
Here's a breakdown of how the program works:
1. The program prompts the user to enter the number of calories and fat grams in the food.
2. Input validation is performed to check if the entered values are valid. If either the calories or fat grams are less than 0, an error message is displayed. Similarly, if the calories from fat are greater than the total calories, another error message is displayed.
3. If the input is valid, the program proceeds to calculate the calories from fat by multiplying the fat grams by 9 (since one gram of fat has 9 calories).
4. The percentage of calories from fat is calculated by dividing the calories from fat by the total calories and multiplying by 100.
5. Finally, the result is displayed, with the percentage rounded to 2 decimal places.
Note: In this program, we assume that the user enters numeric values for the number of calories and fat grams. Additional input validation can be added to handle cases where the user enters non-numeric or invalid values.