CODEWITHSUNDEEP
scala
Vivek
Vivek

Reputation: 3

calling println on a user defined function formatResult 3 times from main, but execution order is different

I am very new to Scala. I tried calling formatResult inside println 3 times from main passing abs, fact, fib in that order.

But the output shows a different execution order - fact, fib, abs

/* MyModule.scala */

object MyModule {

    def abs(n: Int): Int = 
        if(n < 0)
            -n
        else
            n

    def fact(n: Int): Int = {
        def go(n: Int, acc: Int): Int = {
            if(n <= 1)
                acc
            else
                go(n - 1, n * acc)
        }

        go(n, 1)
    }

    def fib(n: Int): Int = {
        def loop(n: Int, prev: Int, curr: Int): Int = {
            if(n == 0)
                prev
            else
                loop(n - 1, curr, prev + curr)
        }

        loop(n, 0, 1)
    }

    private def formatResult(fName: String, placeholder: String, n: Int, f: Int => Int) = {
        val msg = "The %s %s %d is %d"
        msg.format(fName, placeholder, n, f(n))
    }

    def main(args: Array[String]): Unit = 

        println(formatResult("absolute value", "of", -10, abs))
        println(formatResult("factorial", "of", 5, fact))
        println(formatResult("fibonacci number", "at index", 8, fib))
}

/* output */

The factorial of 5 is 120
The fibonacci number at index 8 is 21
The absolute value of -10 is 10

Could someone please explain this to me?

Upvotes: 0

Views: 61

Answers (1)

Samar
Samar

Reputation: 2101

Your main method code is not surround by braces. So your main method becomes just the following:

def main(args: Array[String]): Unit = 

println(formatResult("absolute value", "of", -10, abs))

The other two print lines are executed as the object is setup. So they run before the main method is called. The following will work correctly:

def main(args: Array[String]): Unit = {

    println(formatResult("absolute value", "of", -10, abs))
    println(formatResult("factorial", "of", 5, fact))
    println(formatResult("fibonacci number", "at index", 8, fib))
}

Upvotes: 2

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