快學Scala習題解答 第十一章 操作符

在repl中執行即可得到結果。都是從左至右執行

scala中的操作符就是方法，其優先順序是根據首字母來判斷的，優先順序如下

最高優先順序:除以下字元外的操作符字元

* / % 
+ - 
: = ! 
< > 
& ˆ 
| 非操作符
最低優先順序:賦值操作符

class

fraction(n:int,d:int)

import scala.math.abs

class
fraction(n: int, d: int) 
def-(other:fraction):fraction=
def*(other:fraction):fraction=
def/(other:fraction):fraction=
private
defnewfrac(a:int,b:int):fraction=
}object
test
extends
valf = new fraction(15,-6)
valp = new fraction(20,60)
println(f)
println(p)
println(f + p)
println(f - p)
println(f * p)
println(f / p)
}

class

money(val
dollar:bigint,val
cent:bigint)
def-(other:money):money=
private
deftocent()=
def==(other:money):boolean = this.dollar == other.dollar && this.cent == other.cent
def<(other:money):boolean = this.dollar < other.dollar || (this.dollar == other.dollar && this.cent < other.cent)
override
deftostring = "dollar = " + dollar + " cent = " + cent
}object
money
defmain(args:array[string])
}

class

table
def||(str:string):table=
override
deftostring():string=
}object
table
defmain(args: array[string]) 
}

/\_/\

( ' ' )
(  -  )
| | |
(__|__)
提供將兩個asciiart圖形橫向或縱向結合的操作符。選用適當優先順序的操作符命名。縱向結合的例項
/\_/\     -----
( ' ' )  / hello \
(  -  ) <  scala |
| | |   \ coder /
(__|__)    -----

import collection.mutable.arraybuffer

class
asciiart(str:string)
}  def
this()
def+(other:asciiart):asciiart=
art}  def
*(other:asciiart):asciiart=
override
deftostring()=
ss}}
object
test
extends
vala = new asciiart(""" /\_/\
|( ' ' )
|(  -  )
| | | |
|(__|__)
|""".stripmargin)
valb = new asciiart( """    -----
|  / hello \
| <  scala |
|  \ coder /
|    -----
|""".stripmargin)
println(a + b * b)
println((a + b) * b)
println(a * b)
}

class

bigsequence
defpack():long=
}object
bigsequence
b}  def
main(args: array[string]) 
}

class

matrix(val
x:int,val
y:int)
def+(other:int):matrix=
def*(other:matrix):matrix=
def*(other:int):matrix=
override
deftostring()=
str += "\n"
}str
}}object
matrix
}

class

richfile(val
path:string){}
object
richfile
defif(richfile.path == null) else 
}  def
main(args: array[string]) 
}

class

richfile(val
path:string){}
object
richfile
defif(richfile.path == null) else 
}  def
main(args: array[string]) 
}

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