Learn the syntax, data types, and operations essential for programming in Scala

Become a Scala Developer

In this module, we will learn Scala from the ground up. This module aims to teach us how to write basic programs, assuming we have no prior knowledge of the language. We will start with a brief introduction to Scala to understand its functionality and applications. We will then move discuss the key features and functions of the language (data types, functions, classes, etc.) in detail. In the end, we will have all the basic knowledge of how to program in Scala.

Learn Scala from Scratch

Let’s revisit our summation program using the anonymous function. Before we get started, here is the code we have written so far.




// Higher-order sum function
def sum(f: Int => Int, a: Int, b: Int): Int ={
  if(a>b) 0
  else f(a) + sum(f, a+1, b)
}

// Helper function
def id(x: Int): Int = x

def cube(x: Int): Int = x*x*x

def factorial(x: Int): Int = if (x==0) 1 else x * factorial(x-1)

// Summation Functions
def sumOfInts(a: Int, b: Int) = sum(id, a, b)
def sumofCubes(a: Int, b: Int) = sum(cube,a,b)
def sumOfFactorials(a: Int, b:Int) = sum(factorial,a,b)

To write our summation functions using anonymous functions, we will start by creating our `sum` function the same as before.

def sum(f: Int => Int, a: Int, b: Int): Int ={
  if(a>b) 0
  else f(a) + sum(f, a+1, b)
}

The code for the `sum` function hasn't changed. 

For this version of the program, we aren't required to make helper functions and we can simply start defining our summation functions `sumOfInts`, `sumOfCubes`, and `sumOfFactorials`. Where ever we inserted the helper functions in the previous [program](https://www.educative.io/courses/learn-scala/summation-with-higher-order-functions), we will now insert an anonymous function, i.e., the first argument of `sum`.

### `sumOfInts`

The code for the `sum` function hasn't changed. 

For this version of the program, we aren't required to make helper functions and we can simply start defining our summation functions `sumOfInts`, `sumOfCubes`, and `sumOfFactorials`. Where ever we inserted the helper functions in the previous [program](https://www.educative.io/courses/learn-scala/summation-with-higher-order-functions), we will now insert an anonymous function, i.e., the first argument of `sum`.

# `sumOfInts`

In this lesson, we will see a practical example of anonymous functions and see how they allow you to write concise code.

Summation with Anonymous Functions