It's worth mentioning that Scala doesn't support the operator overloading. You might think that there are no operators at all in Scala.

An alternative syntax for calling a method taking a single parameter is the use of the infix syntax. The infix syntax provides you with a flavor just like you are applying an operator overloading, as like what you did in C++. For example:

val x = 45
val y = 75

In the following case, the + means a method in class Int. The following code is a non-conventional method calling syntax:

val add1 = x.+(y)

More formally, the same can be done using the infix syntax, as follows:

val add2 = x + y

Moreover, you can utilize the infix syntax. However, the method has only a single parameter, as follows:

val my_result = List(3, 6, 15, 34, 76) contains 5

There's one special case when using the infix syntax. That is, if the method name ends with a : (colon), then the invocation or call will be right associative. This means that the method is called on the right argument with the expression on the left as the argument, instead of the other way around. For example, the following is valid in Scala:

val my_list = List(3, 6, 15, 34, 76)

The preceding statement signifies that: my_list.+:(5) rather than 5.+:(my_list) and more formally:

val my_result = 5 +: my_list

Now, let's look at the preceding examples on Scala REPL:

scala> val my_list = 5 +: List(3, 6, 15, 34, 76)
  my_list: List[Int] = List(5, 3, 6, 15, 34, 76)
scala> val my_result2 = 5+:my_list
  my_result2: List[Int] = List(5, 5, 3, 6, 15, 34, 76)
scala> println(my_result2)
  List(5, 5, 3, 6, 15, 34, 76)
scala>

In addition to the above, operators here are just methods, so that they can simply be overridden just like methods.