Fizz Buzz
Fizz buzz是一個教小朋友的數學的團隊遊戲，遊戲的進行是小朋友依序報數，當他報的數是3的倍數時喊出"fizz"，是5的倍數時喊出"buzz"，同時是3也是5的倍數時喊出"Fizz buzz"。
Fizz buzz現在也用來作為企業徵才時的一項題目。
例子
報數喊出的順序如下：
1, 2, Fizz, 4, Buzz, Fizz, 7, 8, Fizz, Buzz, 11, Fizz, 13, 14, Fizz Buzz, 16, 17, Fizz, 19, Buzz, Fizz, 22, 23, Fizz, Buzz, 26, Fizz, 28, 29, Fizz Buzz, 31, 32, Fizz, 34, Buzz, Fizz, ...
模數運算子（Modulus Operator）
模數運算子（Modulus Operator, %）是解題的關鍵，回傳整數除法的餘數：
| Division | Division Result | Modulus | Modulus Result |
|---|---|---|---|
| 1/3 | 0 with a remainder of 3 | 1 % 3 | 1 |
| 5/3 | 1 with a remainder of 2 | 5 % 3 | 2 |
| 16/3 | 5 with a remainder of 1 | 16 % 3 | 1 |
通常要判斷一整數為奇數還是偶數也是用模數運算子（Modulus Operator, %）：
| Modulus | Result | Swift Code | Swift Code Result | Comment |
|---|---|---|---|---|
| 6 % 2 | 0 | let isEven = (number % 2 == 0) |
true |
If a number is divisible by 2 it is even |
| 5 % 2 | 1 | let isOdd = (number % 2 != 0) |
true |
If a number is not divisible by 2 it is odd |
解題
以模數運算子（Modulus Operator, %）解題
以整數除以3的餘數來判斷：
| Modulus | Modulus Result | Swift Code | Swift Code Result |
|---|---|---|---|
| 1 % 3 | 1 | 1 % 3 == 0 |
false |
| 2 % 3 | 2 | 2 % 3 == 0 |
false |
| 3 % 3 | 0 | 3 % 3 == 0 |
true |
| 4 % 3 | 1 | 4 % 3 == 0 |
false |
以整數除以5的餘數來判斷：
| Modulus | Modulus Result | Swift Code | Swift Code Result |
|---|---|---|---|
| 1 % 5 | 1 | 1 % 5 == 0 |
false |
| 2 % 5 | 2 | 2 % 5 == 0 |
false |
| 3 % 5 | 3 | 3 % 5 == 0 |
false |
| 4 % 5 | 4 | 4 % 5 == 0 |
false |
| 5 % 5 | 0 | 5 % 5 == 0 |
true |
| 6 % 5 | 1 | 6 % 5 == 0 |
false |
實作
Swift程式碼實作如下：
func fizzBuzz(numberOfTurns: Int) {
var result = ""
for i in 1...numberOfTurns {
var fizzBuzz : String = ""
if i % 3 == 0 {
fizzBuzz += "Fizz\t\t"
}
if i % 5 == 0 {
fizzBuzz += (result.isEmpty ? "" : " ") + "Buzz\t"
}
if fizzBuzz.isEmpty {
fizzBuzz += "\(i)\t"
}
result += fizzBuzz
}
print(result)
}
fizzBuzz(15)
輸出：
1, 2, Fizz, 4, Buzz, Fizz, 7, 8, Fizz, Buzz, 11, Fizz, 13, 14, Fizz Buzz