5.4 Swift函数的默认参数

/**

5.4-函数的默认参数

*/

let str1 = joinString(s1: "hell",toString: "world")

print(str1)

let str2 = joinString(s1: "hell",toString: "world",joiner: "¥")

print(str2)

let str3 = joinString2(s1: "hellw",joiner: "#")

print(str3)

let str4 = joinString2(s1: "llll",toString: "jijiji")

print(str4)

/**

函数的默认参数 一定是在定义函数的时候做的

*/

// 后面那个 # 就是默认参数,可以是第一个，可以出现在函数形式参数的任意位置

func joinString(s1:String,toString s2:String,joiner s3:String = "#") -> String {

return s1 + s3 + s2

}

func joinString2(s1:String,joiner:String = "#") -> String {

return s1 + joiner + s2

}