打開cmd，輸入scala，進(jìn)入交互模式
scala> val a = 123
a: Int = 123
scala> var s = "java"
s: String = java
scala> s = "scala"
s: String = scala
scala> s
res0: String = scala
scala> val a: Int = 123
a: Int = 123
scala> var s: String = "scala"
s: String = scala
