Thread: strstr problem...

  1. #1
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    Sep 2006
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    26

    strstr problem...

    Okay, I have to do some mini-review for my programming class, but I haven't touched C++ in ~6months or so, so I'm a bit rusty.


    I have to have the user input text, then reject it if it contains profanity.

    this is what I have so far, but I can't seem to get it to work. As you can see, I have the words it's checking for in a seperate file so it's easy to update.


    Code:
    #include <string.h>
    #include <stdio.h>
    #include <iostream>
    #include <fstream>
    
    using namespace std;
    
    
    char str[100];
    string prof1, prof2, prof3, prof4, prof5;
    
    int main()
    {
    	ifstream fin;
    
    	fin.open("profanity.txt");
        char *pdest;
        int  result;
    
    	fin >> prof1 >> prof2 >> prof3 >> prof4 >> prof5;
    
    	string words[5] = {prof1, prof2, prof3, prof4, prof5};
    	cout << "Enter text: ";
    	cin >> str;
    
    	for(int a=1; a<5; a++)
    	{
        pdest = strstr( str, words[a] );
    
        if ( pdest != NULL )
    	{
           cout << "Profanity found!";
    	   return 0;
    	}
        else
           cout << "No profanity found\n";
    	}
    
    	return 0;
    }

    any help would be appreciated. I can't figure this out, it should be pretty easy, and it's driving me nuts!

  2. #2
    Devil's Advocate SlyMaelstrom's Avatar
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    Use the std::string class not character arrays. They're better and they contain their own substr() method which is significantly easier to work with.

    Now for some fundamental problems with your code:

    You're mixing your headers up... <stdio.h> and <string.h> aren't under the standard namespace and are both deprecated (actually they aren't standard C++, at all). You should be using <cstring> for the latter and the former has no reason to be there, at all. It's not being used (it's counterpart is <cstdio> however).

    You're also declaring string objects which aren't defined in <string.h>, they're defined in <string>. You likely lucked out because one of your other libraries includes <string>.

    Your closing brace is missing on your for loop.

    You have an unnecessary return in your if statement.

    ...and this is just bickering, but I would be explicitly closing my ifstream before returning.
    Sent from my iPadŽ

  3. #3
    and the hat of int overfl Salem's Avatar
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    > for(int a=1; a<5; a++)
    Arrays also start at 0
    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.

  4. #4
    Registered User
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    7,366
    >> I can't seem to get it to work.
    What is the problem? A compile error? It always outputs not found? What input are you giving it?

    >> Your closing brace is missing on your for loop.
    I don't think so, the else closing brace is actually for the for loop (the else has no opening brace). Better indentation and more consistent bracing would make it a lot easier to see.

    >> actually they aren't standard C++, at all
    Yes, they are standard. They are just deprecated. They must work on all standards-conformant compilers despite the fact that the C++ versions are preferred.

    >> I would be explicitly closing my ifstream before returning.
    I wouldn't. But I wouldn't quibble either way.

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