Variables and Function in F#

Introduction

Variable and functions both defined with let construct in F#.
Defining a integer variable

let a = 2;
 printfn "%d"a; 
 System.Console.ReadKey(true);

In above snippet we defined a integer variable in F# with let constructs. In F# teypes autemetically get inferred. In above declaration type is automatically get inferred to int.

Output 

The other way we can use language construct is

let var = expr1 in expr2 

we can evaluate the expr1 in expr2. First expr1 will get assigned to var1 and then will get evaluated to expr2.

Defining a function

Below we are defining a function called sqr. It is taking one parameter and calculating the square of the input parameter. 

let sqr n = n*n;;
 let a= sqr 5;;
 printfn "%d"a;;
 System.Console.ReadKey(true);

Output 

Above we saw the input parameter to the function got inferred to int. If we want to override default inference of the type then we need to explicitly tell the language about the type of input parameter.

Defining a function with explicit type at input parameter

let sqr (n:float) = n*n;;
let a= sqr 5.5;;
printfn "%f"a;;
System.Console.ReadKey(true);

Output 

Hopes help and thank you for reading.