Question

This is what I have, I want an output like this

*Main> sumThree
Please enter three integers:
1
2
3
Their sum is: 6
(1,2,3)

I however keep getting , without the summ

*Main> sumThree
Please enter three integers:
1
2
3
Their sum is:
(1,2,3)

---

**summ :: Integer -> Integer -> Integer -> IO Integer
summ x1 x2 x3 = return(x1+x2+x3)
sumThree :: IO (Integer, Integer, Integer)
sumThree = do putStr "Please enter tree integers:"
              x1 <- getInteger
              x2 <- getInteger
              x3 <- getInteger
              putStr "Their Sum is: "
              summ x1 x2 x3
              return(x1,x2,x3)**

Answer 1

You have to actually print the result of summ.

Don’t return in your summ function, so that the function’s result type is Integer as opposed to IO Integer. Then, do

putStr (show (summ x1 x2 x3))

instead of just summ x1 x2 x3.

Also, you do know about the sum built-in (Prelude) function right? It takes an array of Num‘s, so you can just do putStr (show (sum [x1, x2, x3])).