Introduction
Control flow in Cairo allows you to control the execution path of your programs based on conditions and repetition.
Conditional Execution
Use if expressions to execute code based on conditions:
let number = 42;
if number > 0 {
println!("Positive number");
} else if number < 0 {
println!("Negative number");
} else {
println!("Zero");
}
if is an expression, so it can return values:
let result = if condition { 5 } else { 10 };
Loops
Use loop to repeat code.
A loop runs indefinitely unless you stop it; use break to exit the loop when a condition is met.
let mut counter = 0;
loop {
if counter == 5 {
break;
}
println!("Counter: {}", counter);
counter += 1;
}
Loops can return values using break:
let result = loop {
counter += 1;
if counter == 10 {
break counter * 2; // Returns 20
}
};
Use continue to skip to the next iteration:
let mut i = 0;
loop {
i += 1;
if i % 2 == 0 {
continue; // Skip even numbers
}
if i > 10 {
break;
}
println!("{}", i); // Only prints odd numbers
}
Instructions
In this exercise you'll help manage a small bakery's daily operations using Cairo's control flow constructs.
1. Calculate Order Total
Implement calculate_total that calculates the cost of an order based on pastry type and quantity:
- Croissant: 3 coins each
- Muffin: 2 coins each
- Cookie: 1 coin each
calculate_total(Pastry::Croissant, 4) // Returns: 12 (4 * 3)
calculate_total(Pastry::Cookie, 10) // Returns: 10 (10 * 1)
2. Apply Volume Discounts
Implement apply_discount that applies discounts based on order total.
Apply the percentage discount to the total, then round down to the nearest whole coin (floor).
- Orders ≥ 20 coins: 10% discount
- Orders ≥ 10 coins: 5% discount
- Orders < 10 coins: no discount
apply_discount(25) // Returns: 22
apply_discount(15) // Returns: 14
apply_discount(8) // Returns: 8
3. Create Baking Schedule
Implement baking_schedule that creates a daily baking plan.
The bakery bakes in batches of 5 orders per hour:
baking_schedule(18) // Returns: [5, 5, 5, 3] (3 full batches + 3 remaining)
baking_schedule(10) // Returns: [5, 5] (2 full batches)
baking_schedule(3) // Returns: [3] (1 partial batch)
Use appropriate control flow constructs (if/else, loop) to solve each problem efficiently.
Learning Exercise
