int to string question

This is a discussion on int to string question within the C++ Programming forums, part of the General Programming Boards category; I wish to make files for enemies in a gme, but they're so many enemies, that i do not wish ...

  1. #1
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    int to string question

    I wish to make files for enemies in a gme, but they're so many enemies, that i do not wish to do a if else ife to open all of them for battle. I want to randomize an int, and open a file with that number.

    is there a way that i can do this? I have tried making int a = <num>;
    char b = a;
    ifstream fin(b);

    It wouldn't get errors, but it would not open, and i assume that is because it is looking for the ascii symbol.

    Thanks ahead of time.
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  2. #2
    It's full of stars adrianxw's Avatar
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    Use sprintf() or one of the string stream classes.

    int a;
    char FileName[20];
    a = 23;
    sprintf(Filename, "File%n.dat", a); // for example
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    Ill give that a quick try. thanks
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    Code:
    #include <iostream.h>
    #include <stdlib.h>
    #include <fstream>
    #include <conio.c>
    using namespace std;
    int main()
    {
    int a;
    char Filename[20];
    a = 23;
    sprintf(Filename, "%n.txt", a);
    ifstream fin(Filename);
    char ch;
    while(fin.get(ch))
    {
    cout << ch;
    }
    getche();
    }
    The program perfroms an illegle operation and crashes.
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  5. #5
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    sprintf is that way, you probably want
    sprintf(filename,"%d.txt",a);
    %n writes the number of characters written so far to the int pointer in the corsiponding position. So your program wrote 0 to memory location 23, this is rarely a good thing. Be careful of the character after the dot being interpreted as precision as well, if your extention was .5xt you would get "23 xt" (i think) thus you may really want sprintf(filename,"%d\.txt",a);

    All the cool kids use std::ostringstream these days.

    std::ostringstream oss;
    oss << a << ".txt";
    ifstream fin(oss.str().c_str());

    boost::lexical_cast also has it goin on.

    std::string filename = boost::lexical_cast<std::string>(a) + ".txt";
    ifstream fin(filename.c_str());

  6. #6
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    Oh yea? well all the cool kids can kiss my uncool butt! the %d works swell, though i must point out one error in your code
    leave out the '\', or you will get "Unknown esacape sequence"

    Thanks man!

    Now i just need to figure out to print a txt file in dos console with the HP 3820 Deskjet printer, but i cant find a tutorial... (HINT HINT)
    Last edited by Blizzarddog; 11-10-2003 at 10:06 AM.
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    hmmm, "\." should be a legit excape sequence, in fact \q where q is not part of a legit escape sequence should be just q. It's not important. Printing causes endless grief there is a dos "print" command that might work if windows wants it to. I just redirect to a file and open in wordpad if I want a hard copy of something.
    foo > file.txt
    wordpad file.txt
    then click print

  8. #8
    and the hat of int overfl Salem's Avatar
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    > in fact \q where q is not part of a legit escape sequence should be just q.
    Nope - illegal escape sequences require a diagnostic from the compiler.

    All the unused lower case letters are reserved, so you really wouldn't want your code doing something new and interesting just because you used a previously undefined escape sequence.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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    thanks. You can get the project, which you can now add your own enemies, at blizzarddog.tk
    get the music pack as well, and put the music files into the directory of the exe.
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  10. #10
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    Originally posted by Salem

    Nope - illegal escape sequences require a diagnostic from the compiler.

    All the unused lower case letters are reserved, so you really wouldn't want your code doing something new and interesting just because you used a previously undefined escape sequence.
    You have no sense of adventure, also after actually looking up conversion specifications '.' only appears after the % and before conversion type. oops. gcc accepts \. as an escape for '.' don't know why now, might be a bug.

  11. #11
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    odd.. im using Dev CPP with GCC.
    Oh heck, \a doesn't do anything either..
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    oh and uhm, the game is uploaded.
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    Strange, I usually build with -Wall --ansi --pedantic and had that in my Dev-Cpp but some how this project did not "inherit" those settings. I get the warning when I build from the command line but my defaults have been screwed up. Sometimes IDE's apparently save you work by lying to you I guess it does make sence to warn people about slashdot

  14. #14
    and the hat of int overfl Salem's Avatar
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    > You have no sense of adventure
    If you define "adventure" as having to relearn the language everytime you change compiler vendor / version then knock yourself out.

    I found that game became very old very quick a long time ago.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

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