How to swap letters?

[ella]

Basically, I have to open a file (words.txt), which contains all my data (string). So, after I finished opening the file, its contents (let's say, four words), I must swap the letters that composed of that word (e.g. TURING when swap: UTGNIR). This program should be "procedure" (swapping of letters). Can someone help me to start since I only have a few basic knowledge about Turing. I really need help.

[Tony]

You can build this in parts, and then connect them.

Start with reading from a file, and then just printing the words to screen.

Then create a procedure that takes a string as an argument.

Then have the procedure swap the letters in the string.

Finally go back to the part where you were reading words from a file, and instead of printing to screen, direct those words into the procedure instead.

[ella]

How do I call the words in a file individually?

[Tony]

There's a reading-from-file tutorial available through The Turing Walkthrough

[ella]

Thanks. But, can you please show some sample programming structure on how to swap the letters using 'for' loops/loops and/or 'if' structures?

[Tony]

Here's an example of working with letters within a string. This should give you enough tools to figure out swapping.

code:

var word : string := "tony" put word(2) word := 'T' + word(2..*) put word

[ella]

Can I have another question? It's not really related to swapping letters.
I have these codes which convert the user's inputted guess to uppercase.

Turing:

var guess : string function uppercase : string     var letter : string     var asciinum : int     var letters : array 1 .. 26 of string     for b : 1 .. length (guess)         letter := guess (b)         % use chr and ord to convert to uppercase         asciinum := ord (letter)         % check if its already uppercase         if asciinum <= 90 and asciinum >= 65 then             letters (b) := letter         else             asciinum := asciinum - 32             letters (b) := chr (asciinum)         end if     end for     result letters end uppercase

And I also have these codes in which the user will input his guess.

Turing:

procedure guessing     put "Enter your guess"         get guess         if guess = words then             put "You're right!"         else             put "Wrong word."             put "The correct word is: ", words         end if end guessing

My problem is, how would I call the uppercase function in that guessing procedure? If the user will enter his guess, his guess will change into uppercase. Help.

[Tony]

Because the scope of the variable guess is outside of the function, then any changes to it will also persist outside of the function (thus you see it as the user's actual guess being modified). You want to use an argument instead

code:

function uppercase (guess : string) : string    ...

Then

code:

get user_guess if uppercase(user_guess) = words then    ...