递归在纯函数式编程中起着重要作用,而Scala很好地支持递归函数。递归意味着一个函数可以重复调用自己。
尝试以下程序,这是递归的一个很好的示例,其中计算了传递的数字的阶乘。
例
object Demo {
def main(args: Array[String]) {
for (i <- 1 to 10)
println( "Factorial of " + i + ": = " + factorial(i) )
}
def factorial(n: BigInt): BigInt = {
if (n <= 1)
1
else
n * factorial(n - 1)
}
}
将上述程序保存在 Demo.scala 中。以下命令用于编译和执行该程序。
命令
\>scalac Demo.scala \>scala Demo
输出
Factorial of 1: = 1 Factorial of 2: = 2 Factorial of 3: = 6 Factorial of 4: = 24 Factorial of 5: = 120 Factorial of 6: = 720 Factorial of 7: = 5040 Factorial of 8: = 40320 Factorial of 9: = 362880 Factorial of 10: = 3628800
