c++ string creation and file manipulation

This is a discussion on c++ string creation and file manipulation within the C++ Programming forums, part of the General Programming Boards category; how would i go about creating a c++ program that generates strings that range from 1 character to 8 characters ...

  1. #1
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    c++ string creation and file manipulation

    how would i go about creating a c++ program that generates strings that range from 1 character to 8 characters (all asci) in such a way that all possible combinations are recorded in a simple txt file?

  2. #2
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    Hold up, I'm programming something that might answer your question.
    Name: Eric Lesnar
    Learning: C/C++, SDL, WinAPI, OpenGL, and Python
    Compiler: Dev-C++ 4.9.0
    Current Game Project: Acoznict

  3. #3
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    Function pointers are so beautiful. This is the console version of what you're talking about.

    Code:
    void PrintRandomWord( char(*Print)(int), int, const int );
    char PrintLetter( int );
    
    
    void PrintRandomWord( char(*Print)(int rand_max), int max_random, const int MAX )
    {
    
       srand( (int)time );
    
       for(int i=0; i<=MAX; i++)
       {
          cout << Print( max_random );
       }
    
    
    }
    
    
    char PrintLetter( int rand_max )
    {
    
       int random= rand() % rand_max;
    
    
       switch( random )
       {
          case 1:
            return 'A';
           break;
    
          case 2:
            return 'B';
           break;
    
          case 3:
            return 'C';
           break;
    
          case 4:
            return 'D';
           break;
    
          case 5:
            return 'E';
           break;
    
          case 6:
            return 'F';
           break;
    
          default:
            return 'S';
           break;
    
       }
    
    
    }
    
    
    int main( int argc, char *argv[] )
    {
    
         PrintRandomWord( PrintLetter, 6, 5 );
    
    
         cin.get();
         return 0;
    
    }
    Name: Eric Lesnar
    Learning: C/C++, SDL, WinAPI, OpenGL, and Python
    Compiler: Dev-C++ 4.9.0
    Current Game Project: Acoznict

  4. #4
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    thanks for the fast reply, but im sort of a noob to cpp, could you explain that a little

  5. #5
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    The file stream version

    Code:
    #include <fstream> // important
    #include <ctime> //  important
    
    
    void PrintRandomWord( char(*Print)(int), int, const int);
    char PrintLetter( int );
    
    
    void PrintRandomWord( char(*Print)(int rand_max), int max_random, const int MAX )
    {
    
       srand( (int)time );
       ofstream fout;
    
       fout.open("RandomLetters.txt", ios::app);
    
    
       for(int i=0; i<=MAX; i++)
       {
          fout << Print( max_random );
       }
    
       fout.close();
    
    }
    
    
    char PrintLetter( int rand_max )
    {
    
       int random= rand() % rand_max;
    
    
       switch( random )
       {
          case 1:
            return 'A';
           break;
    
          case 2:
            return 'B';
           break;
    
          case 3:
            return 'C';
           break;
    
          case 4:
            return 'D';
           break;
    
          case 5:
            return 'E';
           break;
    
          case 6:
            return 'F';
           break;
    
          default:
            return 'S';
           break;
    
       }
    
    
    }
    
    
    int main( int argc, char *argv[] )
    {
    
         PrintRandomWord( PrintLetter, 6, 5 );
    
    
         cin.get();
         return 0;
    
    }
    Is this what you're talking about? I just now coded those two in a desperate attempt to try and help someone for once in my life.
    Name: Eric Lesnar
    Learning: C/C++, SDL, WinAPI, OpenGL, and Python
    Compiler: Dev-C++ 4.9.0
    Current Game Project: Acoznict

  6. #6
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    A newbie to C++?

    If you're a REAL newbie(like just started a few days ago) then I strongly suggest that you don't feel/worry about file streaming for now. But if you're somewhat intermediate and know some stuff then go ahead and ask me a question about my source code.
    Name: Eric Lesnar
    Learning: C/C++, SDL, WinAPI, OpenGL, and Python
    Compiler: Dev-C++ 4.9.0
    Current Game Project: Acoznict

  7. #7
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    Oh yeah, and try to compile that(I already tested it but it would be better if you compiled it to see what it does).
    Name: Eric Lesnar
    Learning: C/C++, SDL, WinAPI, OpenGL, and Python
    Compiler: Dev-C++ 4.9.0
    Current Game Project: Acoznict

  8. #8
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    when i went to compile it using ms vc++ 6, it gave me 9 errors and 1 warning...

  9. #9
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    --------------------Configuration: generator - Win32 Debug--------------------
    Compiling...
    generator.cpp
    C:\Program Files\Microsoft Visual Studio\MyProjects\Generator\generator.cpp(13) : error C2065: 'ofstream' : undeclared identifier
    C:\Program Files\Microsoft Visual Studio\MyProjects\Generator\generator.cpp(13) : error C2146: syntax error : missing ';' before identifier 'fout'
    C:\Program Files\Microsoft Visual Studio\MyProjects\Generator\generator.cpp(13) : error C2065: 'fout' : undeclared identifier
    C:\Program Files\Microsoft Visual Studio\MyProjects\Generator\generator.cpp(15) : error C2228: left of '.open' must have class/struct/union type
    C:\Program Files\Microsoft Visual Studio\MyProjects\Generator\generator.cpp(15) : error C2653: 'ios' : is not a class or namespace name
    C:\Program Files\Microsoft Visual Studio\MyProjects\Generator\generator.cpp(15) : error C2065: 'app' : undeclared identifier
    C:\Program Files\Microsoft Visual Studio\MyProjects\Generator\generator.cpp(20) : warning C4552: '<<' : operator has no effect; expected operator with side-effect
    C:\Program Files\Microsoft Visual Studio\MyProjects\Generator\generator.cpp(23) : error C2228: left of '.close' must have class/struct/union type
    C:\Program Files\Microsoft Visual Studio\MyProjects\Generator\generator.cpp(76) : error C2065: 'cin' : undeclared identifier
    C:\Program Files\Microsoft Visual Studio\MyProjects\Generator\generator.cpp(76) : error C2228: left of '.get' must have class/struct/union type
    Error executing cl.exe.

    generator.exe - 9 error(s), 1 warning(s)

  10. #10
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    Be sure to include iostream, fstream, ctime, cstdlib

    like so:

    Code:
    #include <iostream> // or #include <iostream.h>
    #include <fstream> // or #include <fstream.h>
    #include <cstdlib>
    #include <ctime>
    Name: Eric Lesnar
    Learning: C/C++, SDL, WinAPI, OpenGL, and Python
    Compiler: Dev-C++ 4.9.0
    Current Game Project: Acoznict

  11. #11
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    fstream.h has all of the file streaming functions and stuff so you need to include it if you're going to open, write to, or read from a .txt file

    Including ctime is fine for my compiler. Your compiler is different so you might have to use time.h instead

    C:\Program Files\Microsoft Visual Studio\MyProjects\Generator\generator.cpp(13) : error C2065: 'ofstream' : undeclared identifier

    That error isn't my fault. ofstream is un-identified because you didn't include fstream. "ofstream" is a output file stream class in fstream.h

    Without including that file, the compiler won't know what that is.
    Name: Eric Lesnar
    Learning: C/C++, SDL, WinAPI, OpenGL, and Python
    Compiler: Dev-C++ 4.9.0
    Current Game Project: Acoznict

  12. #12
    unleashed alphaoide's Avatar
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    Looking at the errors, are you not missing "using namespace std"?

  13. #13
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    ok, this is what i have so far:


    Code:
    #include <iostream> // or #include <iostream.h>
    #include <fstream> // or #include <fstream.h>
    #include <cstdlib>
    #include <time.h>
    
    void PrintRandomWord( char(*Print)(int), int, const int);
    char PrintLetter( int );
    
    
    void PrintRandomWord( char(*Print)(int rand_max), int max_random, const int MAX )
    {
    
       srand( (int)time );
       ofstream fout;
    
       fout.open("RandomLetters.txt", ios::app);
    
    
       for(int i=0; i<=MAX; i++)
       {
          fout << Print( max_random );
       }
    
       fout.close();
    
    }
    
    
    char PrintLetter( int rand_max )
    {
    
       int random= rand() % rand_max;
    
    
       switch( random )
       {
          case 1:
            return 'A';
           break;
    
          case 2:
            return 'B';
           break;
    
          case 3:
            return 'C';
           break;
    
          case 4:
            return 'D';
           break;
    
          case 5:
            return 'E';
           break;
    
          case 6:
            return 'F';
           break;
    
          default:
            return 'S';
           break;
    
       }
    
    
    }
    
    
    int main( int argc, char *argv[] )
    {
    
         PrintRandomWord( PrintLetter, 6, 5 );
    
    
         cin.get();
         return 0;
    
    }
    and it gives me these error messages:
    --------------------Configuration: generator - Win32 Debug--------------------
    Compiling...
    generator.cpp
    c:\program files\microsoft visual studio\myprojects\generator\generator.cpp(14) : error C2065: 'ofstream' : undeclared identifier
    c:\program files\microsoft visual studio\myprojects\generator\generator.cpp(14) : error C2146: syntax error : missing ';' before identifier 'fout'
    c:\program files\microsoft visual studio\myprojects\generator\generator.cpp(14) : error C2065: 'fout' : undeclared identifier
    c:\program files\microsoft visual studio\myprojects\generator\generator.cpp(16) : error C2228: left of '.open' must have class/struct/union type
    c:\program files\microsoft visual studio\myprojects\generator\generator.cpp(16) : error C2653: 'ios' : is not a class or namespace name
    c:\program files\microsoft visual studio\myprojects\generator\generator.cpp(16) : error C2065: 'app' : undeclared identifier
    c:\program files\microsoft visual studio\myprojects\generator\generator.cpp(21) : warning C4552: '<<' : operator has no effect; expected operator with side-effect
    c:\program files\microsoft visual studio\myprojects\generator\generator.cpp(24) : error C2228: left of '.close' must have class/struct/union type
    c:\program files\microsoft visual studio\myprojects\generator\generator.cpp(77) : error C2065: 'cin' : undeclared identifier
    c:\program files\microsoft visual studio\myprojects\generator\generator.cpp(77) : error C2228: left of '.get' must have class/struct/union type
    Error executing cl.exe.

    generator.exe - 9 error(s), 1 warning(s)

  14. #14
    unleashed alphaoide's Avatar
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    Do I have to say it again. Add this line to get rid of all those errors:
    using namespace std;

  15. #15
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    Add "using namespace std; " after all of your includes. I don't think it will get rid of the 'ofstream' error, but it might get rid of some/most/all of your errors, maybe. Try it.
    Name: Eric Lesnar
    Learning: C/C++, SDL, WinAPI, OpenGL, and Python
    Compiler: Dev-C++ 4.9.0
    Current Game Project: Acoznict

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