Control Flow Practice

// ===== CONTROL FLOW PRACTICE =====

// Challenge 1: FizzBuzz
print("--- FizzBuzz ---")
for i in 1...20 {
    if i % 3 == 0 && i % 5 == 0 {
        print("FizzBuzz")
    } else if i % 3 == 0 {
        print("Fizz")
    } else if i % 5 == 0 {
        print("Buzz")
    } else {
        print(i)
    }
}

// Challenge 2: Grade Calculator
print("\n--- Grade Calculator ---")
let scores = [95, 82, 76, 68, 55, 91]

for score in scores {
    let grade: String
    switch score {
    case 90...100: grade = "A"
    case 80..<90: grade = "B"
    case 70..<80: grade = "C"
    case 60..<70: grade = "D"
    default: grade = "F"
    }
    print("Score \(score) = Grade \(grade)")
}

// Challenge 3: Find Prime Numbers
print("\n--- Prime Numbers (1-50) ---")
var primes: [Int] = []

for num in 2...50 {
    var isPrime = true

    for divisor in 2..<num {
        if num % divisor == 0 {
            isPrime = false
            break
        }
    }

    if isPrime {
        primes.append(num)
    }
}
print(primes)

// Challenge 4: Number Guessing Game
print("\n--- Guessing Game ---")
let secret = 7
var guess = 0
var attempts = 0

while guess != secret {
    attempts += 1
    guess = Int.random(in: 1...10)

    if guess < secret {
        print("\(guess) - Too low!")
    } else if guess > secret {
        print("\(guess) - Too high!")
    } else {
        print("\(guess) - Correct in \(attempts) tries!")
    }
}

// Challenge 5: Validate User Input
print("\n--- Input Validation ---")
func validateUser(name: String?, email: String?, age: Int?) -> Bool {
    guard let userName = name, !userName.isEmpty else {
        print("Error: Name required")
        return false
    }

    guard let userEmail = email, userEmail.contains("@") else {
        print("Error: Valid email required")
        return false
    }

    guard let userAge = age, userAge >= 13 else {
        print("Error: Must be 13 or older")
        return false
    }

    print("Welcome, \(userName)!")
    return true
}

validateUser(name: nil, email: "[email protected]", age: 15)
validateUser(name: "Bob", email: "invalid", age: 15)
validateUser(name: "Alice", email: "[email protected]", age: 10)
validateUser(name: "Charlie", email: "[email protected]", age: 16)

// Challenge 6: Pattern with nested loops
print("\n--- Triangle Pattern ---")
for row in 1...5 {
    var line = ""
    for _ in 1...row {
        line += "* "
    }
    print(line)
}