Scala Learning note 4--scala's function one

Default value:

def saymyname (name:string = "Jack") {println (name)}

Variable parameters:

def summoreparameters (elem:int*) = {  var sum = 0for (e <-elem) {println (e) sum + = e}  sum}

Use of underscores:

def add (a:int,b:int) = a+bdef add2  = Add (_:int,2)

Recursive functions: Need to explicitly give the return type of the function

def FAC (n:int): Int = if (n <= 0) 1 Else n*fac (n-1)

function currying:

Write this argument independently, this is currying

def mulitply (X:int) (y:int) = x*ydef m2 = mulitply (2) _;

Curry is the parameter can be separated, some of the function parameters can be underlined to replace

How anonymous functions are declared

Val t = () =>333

: followed by the data type, C for the passed in parameters

def TESTFUNC02 (c: () =>int) {      println (c ())      1000}

anonymous functions

Val D1 = (a:int) = = a+100;

The anonymous function as a parameter is actually the parameter name, followed by the argument type, then the expression

Def TESTF1 (callback: (Int,int) =>int) ={    println (Callback (123,123));}

Nested function, in fact, is a def inside a set of Def

def add3 (X:int, Y:int, z:int): int = {def add2 (X:int, y:int): int = {x + y}add2 (add2 (x, y), Z)}

def sum (f:int = int): (int, int) + int = {    def sumf (A:int, b:int): int =       if (a >b) 0 else F ( A) + SUMF (A + 1, b)     SUMF}

Scala Learning note 4--scala's function one