Error on my Haskell code

Question

I get this error on my code:

"parse error (possibly incorrect indentation or mismatched brackets)"

max3 a b c = if a>b && a>c then show a
     else if b>a && b>c then show b
     else if c>a && c>b then show c

i need to get the higher number between a, b and c

EDIT: After adding the else clause as suggested:

max3 a b c = if a>b && a>c then show a
     else if b>a && b>c then show b
     else if c>a && c>b then show c
     else show "At least two numbers are the same"

now i get this error " parse error on input `if' "

EDITED as suggested!

EDITED: SOLVED, i did with guards like shree.pat18 said! Ty!

Your current code loads fine for me. Maybe there's something else in your file that causes trouble? — tempestadept
– tempestadept, Commented Jul 18, 2014 at 7:57

shree.pat18 · Accepted Answer · 2014-07-18 06:05:17Z

2

As John L mentions in the comments, you need a final else clause to catch the case when none of your conditions is true.

Alternatively, you may use guards instead of if..else if, like so:

max3 a b c 
          | a > b && a > c = show a
          | b > a && b > c = show b
          | c > a && c > b = show c
          | otherwise = show "At least two numbers are the same"

edited Jul 18, 2014 at 6:05

answered Jul 18, 2014 at 4:20

shree.pat18

21.8k3 gold badges45 silver badges65 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Juan Figueira Over a year ago

max3 a b c if a>b && a>c then show a else if b>a && b>c then show b else if c>a && c>b then show c else show "The numbers are the same" i added else and now appear this "parse error on input `if'"

shree.pat18 Over a year ago

Please add your updated code into your question. Also, did you try my updated code which uses guards?

Franky Over a year ago

The conditions are non-exhaustive. a=b=2, c=1. Always use otherwise.

Juan Figueira Over a year ago

i used otherwise and i still get error "parse error on input `if'"

Boyd Stephen Smith Jr. · Accepted Answer · 2014-07-18 23:13:25Z

1

import Data.List (maximum)

max3 a b c = maximum [a, b, c]

Fuhgeddaboudit.

answered Jul 18, 2014 at 23:13

Boyd Stephen Smith Jr.

3,20216 silver badges39 bronze badges

2 Comments

Juan Figueira Over a year ago

i need to create the function, its an exercise that need to my class!

Boyd Stephen Smith Jr. Over a year ago

But, you did create the function. Why can you use show, &&, and >, all defined by the standard library (not the language) but you can't use maximum also defined by the standard library?

Collectives™ on Stack Overflow

Error on my Haskell code

2 Answers 2

4 Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related