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Have you ever wondered how public transit systems calculate bus fares, especially when it comes to discounts for kids and seniors? Let's dive into the world of Boolean expressions and if statements to uncover the mystery.
Imagine you're tasked with designing a program for a public transit system that determines a passenger's bus fare. The standard fare is $4.25, but there are special discounts. Kids under five ride for free, while seniors aged 60 and over get a dollar off. How do you implement this in a program? Let's break it down step by step.
The first piece of the puzzle is to identify whether a passenger qualifies as a kid. For our purposes, a kid is defined as anyone under five years old. This requires us to ask the user for their age and create a Boolean expression to check if they meet the criteria.
python
age = int(input("Please enter your age: "))
is_kid = age < 5
But hold on, there's a catch. If you input the age as a string, comparing it to an integer will result in a TypeError. We need to cast the input to an integer to avoid this issue.
Let's test our Boolean expression. If the user enters an age less than five, the fare should be zero. We input ages three, five, and six to verify our logic. The result? Perfect! Passengers under five get a free ride, while those aged five and above do not.
With our Boolean expression working, we can now incorporate it into an if statement. If the condition is true, the fare is set to zero.
python
if is_kid:
bus_fare = 0
Next, we need to handle the senior discount. Seniors are defined as those aged 60 and over. This time, our Boolean expression checks if the age is greater than or equal to 60.
python
is_senior = age >= 60
If the condition is met, we subtract a dollar from the standard fare. This approach is future-proof, allowing easy adjustments to the base fare without affecting the discount.
python
if is_senior:
bus_fare = 4.25 - 1
The transit authority wants the app to inform passengers about the fare type they qualify for. To achieve this, we introduce a new variable fare_type and set it based on the conditions met.
python
if is_kid:
bus_fare = 0
fare_type = "kids"
elif is_senior:
bus_fare = 4.25 - 1
fare_type = "senior"
else:
bus_fare = 4.25
fare_type = "standard"
Finally, we print the fare type and the calculated fare.
python
print(f"The {fare_type} bus fare is ${bus_fare:.2f}")
We test all possible scenarios: kids, seniors, and standard passengers. Initially, we encounter a NameError because fare_type is not defined outside the if statements. To resolve this, we initialize the variable before the conditions.
python
fare_type = "standard" # Default fare type
And there you have it! A program that calculates bus fares based on age, complete with discounts for kids and seniors. By using Boolean expressions and if statements, we've created a system that is both efficient and user-friendly. As we wrap up, let's return to our initial question: How do you design a fare calculation app that meets these unique requirements? The answer lies in the logic we've just explored.
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