Comparing input

This is a discussion on Comparing input within the C++ Programming forums, part of the General Programming Boards category; Hey all, heres my deal. I need to take in user input, and compare it to pre-defined information. The user ...

  1. #1
    RoD
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    Comparing input

    Hey all, heres my deal. I need to take in user input, and compare it to pre-defined information. The user says something and the computer reacts after checking for appropriate match. Its a chatting program.I want to use a setup like this:

    Code:
    cout<<"Input something: ";
    cin<<input
    
    if (input != " ")
    {
    struct Check1
    {
    <predefined keyword>
    or
    <predefined keyword>
    or
    <predefined response>
    }
    
    if (Check1 == true)
    {
    cout<<predefined response<<"\n";
    }
    
    else:
    
    }
    }
    
    goto Check2

    Now i realize this isn't real code, but this is the idea i want, any ideas how i could do this?

  2. #2
    Confused Magos's Avatar
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    Code:
    void DoSomething(char* String)
    {
       if(strcmp(String, "Keyword1") == 0)
       {
          //Do something
       }
       else if(strcmp(String, "Keyword2") == 0)
       {
          //Do something else
       }
       else if(strcmp(String, "Keyword3") == 0)
       {
          //Do something else
       }
       else 
       {
          //Do something else
       }
    }
    MagosX.com

    Give a man a fish and you feed him for a day.
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  3. #3
    RoD
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    will this work if the keyword is in a sentence rather then the only imput?

    Example:

    Hello i am "keyword here" today.

    as opposed to

    keyword

  4. #4
    BMJ
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    Magos is telling you that you cannot compare inputted strings with the == operator... you need to use strcmp()

  5. #5
    Guest Sebastiani's Avatar
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    Yes, and as far as substrings, well, you are going to have to split them up yourself! The function might have this signature:

    Code:
    /*...returns false at end of string...*/
    bool GetNextWord( char sentence[], int * next_position, char recieve_buff); 
    
    int main() {
    char sentence[] = "This string will get parsed";
    char parsed[] = "parsed";
    char word[100];
    int next = 0;
    
      while( GetNextWord( sentence, &next, word ) ) {
        printf("\n%s", word);
          if( strcmp(word, parsed) == 0) {
           printf(" matches %s.", parsed); 
        getch();
       }
    
     return 0;
    }
    Code:
    #include <cmath>
    #include <complex>
    bool euler_flip(bool value)
    {
        return std::pow
        (
            std::complex<float>(std::exp(1.0)), 
            std::complex<float>(0, 1) 
            * std::complex<float>(std::atan(1.0)
            *(1 << (value + 2)))
        ).real() < 0;
    }

  6. #6
    Registered User
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    Or you could use std::string:

    Code:
    #include <string>
    #include <iostream>
    
    int main()
    {
    
    	string s;
    
    	cout<<"Enter a string: ";
    	cin>>s;
    
    	string::size_type pos = s.find(string("keyword"));
    
    	if ( pos != string::npos )
    	{
    		cout<<"Found keyword at "<<pos<<endl;
    	}
    
    	return 0;
    }
    The crows maintain that a single crow could destroy the heavens. Doubtless this is so. But it proves nothing against the heavens, for the heavens signify simply: the impossibility of crows.

  7. #7
    RoD
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    thnx if i think i like that one.

    edit:// Errors suck:

    PHP Code:
    --------------------Configurationtest Win32 Debug--------------------
    Compiling...
    test.cpp
    C
    :\Documents and Settings\NEKEY\Desktop\test.cpp(7) : error C2065'string' undeclared identifier
    C
    :\Documents and Settings\NEKEY\Desktop\test.cpp(7) : error C2146syntax error missing ';' before identifier 's'
    C:\Documents and Settings\NEKEY\Desktop\test.cpp(7) : error C2065's' undeclared identifier
    C
    :\Documents and Settings\NEKEY\Desktop\test.cpp(9) : error C2065'cout' undeclared identifier
    C
    :\Documents and Settings\NEKEY\Desktop\test.cpp(9) : error C2297'<<' illegalright operand has type 'char [17]'
    C:\Documents and Settings\NEKEY\Desktop\test.cpp(10) : error C2065'cin' undeclared identifier
    C
    :\Documents and Settings\NEKEY\Desktop\test.cpp(10) : warning C4552'>>' operator has no effectexpected operator with side-effect
    C
    :\Documents and Settings\NEKEY\Desktop\test.cpp(12) : error C2653'string' is not a class or namespace name
    C
    :\Documents and Settings\NEKEY\Desktop\test.cpp(12) : error C2065'size_type' undeclared identifier
    C
    :\Documents and Settings\NEKEY\Desktop\test.cpp(12) : error C2146syntax error missing ';' before identifier 'pos'
    C:\Documents and Settings\NEKEY\Desktop\test.cpp(12) : error C2065'pos' undeclared identifier
    C
    :\Documents and Settings\NEKEY\Desktop\test.cpp(12) : error C2228left of '.find' must have class/struct/union type
    C
    :\Documents and Settings\NEKEY\Desktop\test.cpp(14) : error C2653'string' is not a class or namespace name
    C
    :\Documents and Settings\NEKEY\Desktop\test.cpp(14) : error C2065'npos' undeclared identifier
    C
    :\Documents and Settings\NEKEY\Desktop\test.cpp(16) : error C2297'<<' illegalright operand has type 'char [18]'
    C:\Documents and Settings\NEKEY\Desktop\test.cpp(16) : error C2065'endl' undeclared identifier
    Error executing cl
    .exe.

    test.obj 15 error(s), 1 warning(s
    Last edited by RoD; 10-20-2002 at 06:58 PM.

  8. #8
    Guest Sebastiani's Avatar
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    did you forget:

    #include <string>
    #include <iostream>

    ?

    Also, that solution won't work, because it assumes that the keywords are already separated. However, you could use the string::find_first_not_of() function, but you'll have to ask an STL'er about that one...
    Code:
    #include <cmath>
    #include <complex>
    bool euler_flip(bool value)
    {
        return std::pow
        (
            std::complex<float>(std::exp(1.0)), 
            std::complex<float>(0, 1) 
            * std::complex<float>(std::atan(1.0)
            *(1 << (value + 2)))
        ).real() < 0;
    }

  9. #9
    Rebooted Inquirer's Avatar
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    Ummm... I am not quite sure about this one, but i have heard say about a strtok() function tht tokenizes strings... try the msdn...
    Hope this helps:
    ~Inquirer
    Compilers:
    GCC on Red Hat 8.1 (Primary)
    GCC on Mac OS X 10.2.4 (Secondary)

    Others:
    MinGW on XP

  10. #10
    RoD
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    did you forget:

    #include <string>
    #include <iostream>
    No. I added .h to the end of them and took it down to ten errors:

    PHP Code:
    --------------------Configurationtest Win32 Debug--------------------
    Compiling...
    test.cpp
    c
    :\documents and settings\nekey\desktop\test.cpp(7) : error C2065'string' undeclared identifier
    c
    :\documents and settings\nekey\desktop\test.cpp(7) : error C2146syntax error missing ';' before identifier 's'
    c:\documents and settings\nekey\desktop\test.cpp(7) : error C2065's' undeclared identifier
    c
    :\documents and settings\nekey\desktop\test.cpp(12) : error C2653'string' is not a class or namespace name
    c
    :\documents and settings\nekey\desktop\test.cpp(12) : error C2065'size_type' undeclared identifier
    c
    :\documents and settings\nekey\desktop\test.cpp(12) : error C2146syntax error missing ';' before identifier 'pos'
    c:\documents and settings\nekey\desktop\test.cpp(12) : error C2065'pos' undeclared identifier
    c
    :\documents and settings\nekey\desktop\test.cpp(12) : error C2228left of '.find' must have class/struct/union type
    c
    :\documents and settings\nekey\desktop\test.cpp(14) : error C2653'string' is not a class or namespace name
    c
    :\documents and settings\nekey\desktop\test.cpp(14) : error C2065'npos' undeclared identifier
    Error executing cl
    .exe.

    test.obj 10 error(s), 0 warning(s

  11. #11
    Just a Member ammar's Avatar
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    Hi,
    I don't think that if you are making a chat program your only problem will be tokenizing or comparing the text( I mean doing the coding), because it's not complicated, but I think that the problem is in how to deal with the entered keywords, and respond to them, because in order to make a good chatting program it will be VERY hard.

  12. #12
    RoD
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    This one is a sub-par version for a buddies english project (he was given permission to submit a program not made by him in conjunction with his paper).

    Hes going to give me a list of questions and responses, i just have to figure out how its going to pick out certain words, example:

    Question: Can u pick up that paper?

    picks out: pick up

    says: I would but i have no arms

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