Re: Finding string characters

[Barry Schwarz]

On Tue, 19 May 2020 15:21:23 -0700 (PDT), Ain? Paplauskait?
<ainepapl...@gmail.com> wrote:

>Hello! I am making Hangman game with FLTK. I have a problem - I would like my function to compare each letter of the string word_4 to a certain character(entered from input widget). For example, my string word is

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[Paavo Helde]

20.05.2020 01:21 Ainė Paplauskaitė kirjutas:
> Hello! I am making Hangman game with FLTK. I have a problem - I would like my function to compare each letter of the string word_4 to a certain character(entered from input widget). For example, my string word is "sun" and I would like to compare the first letter with the entered letter(from input). So I need to compare 's' with string 's'.
> There is part of the code:

Your code is not complete, contains references to undefined types, does
not compile and does not have a main() function. So it's hard to tell
anything about this, especially given that your only complaint is "does
not work".

My first recommendation is to get rid of all dangerous C-style
anachronisms like void* parameters, C-style arrays, strcpy(). Also raw
pointers and reinterpret_cast should not be needed in such a simple
program. At first glance it looks like the C-style
array-decay-to-pointer misfeature is the immediate cause of your
problems, so why not get rid of it and to concentrate on learning one
language, not a bad mix of two.


>
> struct Dictionary
> {
> string Word_4[150];
> string file_4;
> string word_4;
> };
>
> struct Info
> {
> Fl_Input* instr;
> char sval[40];
> };
>
> void readLetter_4(string Word_4[], string &word_4){
>
> vector<string> words;
> ifstream file("letter_4.txt");
> string line;
> if (!file)
> printf("File does not exist");
> else
> while (getline(file, line))
> {
> words.push_back(line);
> srand(time(0));
> }
>
> word_4 = words[rand() % words.size()];
> file.close();
> }
>
> void showLetters_cb(Fl_Widget* w, void* param) {
>
> string word_4; string Word_4[150];
> Info* input= reinterpret_cast<Info*>(param);
> strcpy(input->sval, input->instr->value());
> readLetter_4(Word_4, word_4);
>
> if (word_4.at(0) == (input->sval)) //this does not work
> {
> raide14->value(zodis_4.at(0));
> }
>
> /*if (word_4[1] == (limput->sval)) //This kind of comparing does not work. How could I fix this?
> {
> raide14->value(word_4 + 1, 1);
> }
>
> }*/
>
> }
>

[Öö Tiib]

On Wednesday, 20 May 2020 01:21:33 UTC+3, Ainė Paplauskaitė wrote:
> Hello! I am making Hangman game with FLTK. I have a problem - I would like my function to compare each letter of the string word_4 to a certain character(entered from input widget). For example, my string word is "sun" and I would like to compare the first letter with the entered letter(from input). So I need to compare 's' with string 's'.

If you need to find position of char c in std::string s then why
do not you use string's member find() like s.find(c) ?

<https://en.cppreference.com/w/cpp/string/basic_string/find>

> There is part of the code:
>

[Jorgen Grahn]

On Wed, 2020-05-20, Paavo Helde wrote:
> 20.05.2020 01:21 Ainė Paplauskaitė kirjutas:

>> Hello! I am making Hangman game with FLTK. I have a problem - I
>> would like my function to compare each letter of the string word_4
>> to a certain character(entered from input widget). For example, my
>> string word is "sun" and I would like to compare the first letter
>> with the entered letter(from input). So I need to compare 's' with
>> string 's'. There is part of the code:
>
> Your code is not complete, contains references to undefined types, does
> not compile and does not have a main() function. So it's hard to tell
> anything about this, especially given that your only complaint is "does
> not work".

> My first recommendation is to get rid of all dangerous C-style
> anachronisms like void* parameters,

I bet that comes from that FLTK library or framework he's using.
That's a valid use case for void* and reinterpret_cast.

> C-style arrays, strcpy(). Also raw
> pointers and reinterpret_cast should not be needed in such a simple
> program. At first glance it looks like the C-style
> array-decay-to-pointer misfeature is the immediate cause of your
> problems, so why not get rid of it and to concentrate on learning one
> language, not a bad mix of two.

Yes; his code should leave the C world earlier; use std::vector or
std::array instead of C arrays of strings; use std::string instead of
C arrays of char.

>> struct Dictionary
>> {
>> string Word_4[150];
>> string file_4;
>> string word_4;
>> };

I also don't understand what the _4 suffix is doing everywhere, and
why a dictionary contains 150 words, and one extra word.

Ah, I think I see now -- you sometimes play Hangman with four-letter
words. Shouldn't affect the naming of variables and members,
though.

Personally I would write classes for the core of the game and then
maybe write unit tests before I wrote the UI. Something like:

class Game {
public:
explicit Game(const string& answer);
// e.g. "_oo_ar"
void put(std::ostream&) const;
size_t size() const;
bool solved() const;
// total failed guesses
size_t mistakes() const;

// guess that the string is s; returns
// the number of errors in the guess/how much
// the hanged man should grow
size_t guess(const string& s);
};

/Jorgen

--
// Jorgen Grahn <grahn@ Oo o. . .
\X/ snipabacken.se> O o .