Comparing strings...

This is a discussion on Comparing strings... within the C Programming forums, part of the General Programming Boards category; Hi, I tried comparing the strings as follows but it doens't work. Pls tell me the correct way, thnx a ...

  1. #1
    Registered User Nutshell's Avatar
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    Comparing strings...

    Hi,

    I tried comparing the strings as follows but it doens't work. Pls tell me the correct way, thnx a lot:

    Code:
    char string = "yyy";
    
    if ( string == "yyy" )
       printf( "match" );
    else
       printf( "doesn't match" );

  2. #2
    Hamster without a wheel iain's Avatar
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    you cant use the equality operator on strings it doesnt work, use this method

    #include<string.h>

    char[32] string1;
    char[32] string2;

    if(strcmp(string1, string2)==NULL)
    {
    cout<<"they are equal";
    }
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  3. #3
    Registered User Nutshell's Avatar
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    so i can't do it just by ordinary code or do it by scratch is that what you mean?

    thnx

  4. #4
    Mayor of Awesometown Govtcheez's Avatar
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    I could be wrong, but K & R says strcmp returns 0 when they're equal.

  5. #5
    Registered User Nutshell's Avatar
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    k thnx

  6. #6
    Hamster without a wheel iain's Avatar
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    yep sorry,my mistake
    that part of the code should have been

    !=NULL

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  7. #7
    Mayor of Awesometown Govtcheez's Avatar
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    I think you actually want:

    if(strcmp(string1, string2)==0)
    {
    cout<<"they are equal";
    }

  8. #8
    train spotter
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    >>so i can't do it just by ordinary code or do it by scratch is that what you mean?

    Yes you can.

    First the strings must be the same length ( strlen() or lstrlen() ) and then you will have to loop thru each string testing each index individually.

    Code:
    if(lstrlen(sString1)!=lstrlen(sString2))
         return FALSE;//no match
    for(i=0;i<lstrlen(sString1);i++)
    {
         if(sString1[i]!=sString2[i])
              return FALSE;//no match so exit
    }
    return TRUE;//got this far must be match
    As you can see using strcmp() is easier.
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  9. #9
    the Corvetter
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    Yes, you could either use strcmp or test how novacain said to. The reason being is when you say:
    Code:
    if (string1 == string2)
    These are char arrays and when you don't use the brackets to specify an element, then you start comparing addresses of the arrays. Of course, unless they are at the same address in mem, it will always turn out, "no".
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