hi i m new to Haskell, i need help in the deposit money in this simple atm bank system
the problem shown during enter amount on deposit" Program error: Prelude.read: no parse"
below is the code.Please help.Thank you

import System.IO


start :: IO ()
start = do 
	putStrLn "------------------"
	putStrLn "---- ATM Bank ----"
	putStrLn "------------------"
	putStrLn ""
	putStrLn "1- Login"
	putStrLn ""
	putStrLn "2- Exit"
	putStrLn ""
	putStrLn "Enter your choice: "
	
	opt <- getLine
	if (opt == "1") 
	then do 
		validation		
	else
		do
		putStrLn "Thank you for using Bank ATM"		

mainMenu :: IO ()
mainMenu =
	do 
	putStrLn "------------------"
	putStrLn "---- ATM Bank ----"
	putStrLn "------------------"
	putStrLn ""
	putStrLn "1- Check Balance"
	putStrLn ""
	putStrLn "2- Withdraw"
	putStrLn ""
	putStrLn "3- Deposit"
	putStrLn ""
	putStrLn "4- Change Password"
	putStrLn ""
	putStrLn "5- Back"
	putStrLn ""
	putStrLn "Enter your choice: "	 
	opt <- getLine
	
        if(opt == "1") then do balance
         else do
        if(opt == "2") then do withdraw      
	 else do
        if(opt == "3") then do deposit  
	 else do
        if(opt == "4") then do changePW 
        else
	 do 
	  start
	
balance :: IO ()
balance =
	do
	 putStrLn "Your balance is: "
	 bal <- readFile "Balance.txt"
	 putStrLn bal
	 mainMenu 

withdraw :: IO ()
withdraw =
	do
	 putStrLn "Enter the amount: "
 	 b <- getLine	
	 bal <- readFile "Balance.txt"
	 
 	 let wb = read b :: Int
 	 let obal = read bal :: Int
	 if (wb < obal) then
	  do
	   let total = obal - wb
	   let t = show total

	   writeFile "Balance.txt" t	
	   mainMenu 
	 else
	  do
	    putStrLn "Amount is not valid"
	    mainMenu 


deposit :: IO()	
deposit =
	do
	putStrLn "Enter the amount: "
	a <- getLine 	
	bal <- readFile "Balance.txt"

	let amt = read a :: Int
	let obal = read bal :: Int
	
	let total = amt + obal
	let t = show total

	writeFile "Balance.txt" t	
	mainMenu  

changePW :: IO ()
changePW =
	do
	 putStrLn "Enter new PIN number: "
	 nPIN <- getLine
	 writeFile "Password.txt" nPIN	
	 mainMenu 		

validation :: IO ()
validation =
	do
	putStrLn ""
	putStrLn "Enter your PIN Number: "
	kPIN <- getLine
	inPIN <- readFile "Password.txt"
	if (kPIN == inPIN) 
	 then
  	  do	
		mainMenu
	 	else
	   do	
		putStrLn "Wrong PIN number"
		putStrLn ""
		start

have you solved it already ? i am also looking for it =x=
presentation soon~

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.