f# Ex 3.1

// Exercise 3.1 – Pattern matching and recursion
// a. Define a function vowelToUpper c that converts the characters a, e, i, o
// and u to capitals (upper case). All other characters should be returned unchanged.
// You are not allowed to use the standard F# method.ToUpper() on strings!




open System

let vowelToUpper (c:char):char=
    if (c = 'a') then 'A'
    else if (c = 'e') then 'E'
    else if (c = 'i') then 'I'
    else if (c = 'o') then 'O'
    else if (c = 'u') then 'U'
    else c


printfn "%c" (vowelToUpper('e'))

Console.ReadKey() |> ignore




// b. Define another function (choose your own function name) to convert all
// occurrences of a, e, i, o, and u in a string to capitals. Write the function to use
// recursion and the vowelToUpper in 3.1a above



open System

let vowelToUpper (c:char):char=
    if (c = 'a') then 'A'
    else if (c = 'e') then 'E'
    else if (c = 'i') then 'I'
    else if (c = 'o') then 'O'
    else if (c = 'u') then 'U'
    else c

let allVowel(s:string) = String.collect (fun c -> sprintf"%c" (vowelToUpper(c))) s

printfn "%s" (allVowel("rohit biswas"))
Console.ReadKey() |> ignore