High order functions are functions that either take other functions as parameters or return functions. They allow functions to be passed into other functions as arguments and support abstraction. Some key advantages are that they can reduce program size, accelerate development for large programs, and have zero runtime cost in many cases by supporting abstraction and code reuse through passing functions as arguments.

1. HIGH ORDER
FUNCTIONS

2. Whats are high order functions?
• One or more of its parameters is a function, and it returns
some value.
• It returns a function, but none of its parameters is a
function.
• One or more of its parameters is a function, and it returns
a function.

3. • def isEqualToFour(a:Int) = a == 4
• val list = List(1, 2, 3, 4)
• val resultExists4 = list.exists(isEqualToFour)

4. def sumInts(a: Int, b: Int): Int =
if (a > b) 0 else a + sumInts(a + 1, b)

5. Advantages
• Higher-order functions reduce program size and
accelerate development speed, particularly for large
programs.
• Expressiveness of a visual syntax
• Zero run-time cost in most cases

6. Thanks