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must be a modifiable lvalue error

This is a discussion on must be a modifiable lvalue error within the C++ Programming forums, part of the General Programming Boards category; This is supposed to remove vowels from a word. However the .at doesnt work, it says the 'a' has to ...

  1. #1
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    must be a modifiable lvalue error

    This is supposed to remove vowels from a word. However the .at doesnt work, it says the 'a' has to be a modifiable lvalue... what does that mean?

    Code:
    #include <string>
    #include <iostream>
    using namespace std;
      
    void vowelremover(string&);
    string word;
    int main ()
    { 
     
        cout << "Enter a word of which you want the vowels removed: ";
        cin >> word;
     
    	vowelremover(word);
     
    	cout << "The word without vowels is: " << word << endl;
    	return 0;
    
    
     }
     
     
    
    
    void vowelremover (string& enteredword)
    {
    	int posvowel;
    	int i;
    
    
     for (i == 0; i < enteredword.length(); i ++)
    	 {
    	 while (enteredword.at(i) = 'a' || enteredword.at(i) = 'e' || enteredword.at(i) = 'i' || enteredword.at(i) = 'o' || 
    		 enteredword.at(i) = 'u' || enteredword.at(i) = 'A' || enteredword.at(i) = 'E' || enteredword.at(i) = 'I' || enteredword.at(i) = 'O' || 
    		 enteredword.at(i) = 'U')
    	
    		{
    			 enteredword.erase(i, 1);
    			i == 0;
    		 }
    	 
    	 }
    }

  2. #2
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    It means you're mixing up assignment operators (=) with equality operators (==) in multiple places.
    stahta01 likes this.

  3. #3
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    double equal signs doesnt work though...

  4. #4
    C++ Witch laserlight's Avatar
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    How do they fail to work?
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  5. #5
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    "Doesn't work" is a vague and useless description of your problem. For the best assistance, post the updated code along with all warning/error messages you've received.

  6. #6
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    Oh wow I'm stupid. The double equal signs seems to work, but when i run the program it says i'm using i without initializing it.

  7. #7
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    That's probably because you're also mixing up with equality operators (==) with assignment operators (=).

  8. #8
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    Okay the error is now "Unhandled exception at 0x770b15de in FinishedLab6.exe: Microsoft C++ exception: std:ut_of_range at memory location 0x0020f7f8.." I've had this error before but can't remember how I fixed it.
    Last edited by poolofdeath; 03-26-2013 at 08:58 PM.

  9. #9
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    Post that version of the code, please.
    laserlight likes this.

  10. #10
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    Code:
    #include <string>
    #include <iostream>
    using namespace std;
       
    void vowelremover(string&);
    string word;
    int main ()
    { 
      
        cout << "Enter a word of which you want the vowels removed: ";
        cin >> word;
      
        vowelremover(word);
      
        cout << "The word without vowels is: " << word << endl;
        return 0;
     
     }
      
      
     
    void vowelremover (string& enteredword)
    {
        int posvowel;
        int i;
     
     
     for (i = 0; i < enteredword.length(); i ++)
         {
         while (enteredword.at(i) == 'a' || enteredword.at(i) == 'e' || enteredword.at(i) == 'i' || enteredword.at(i) == 'o' || 
             enteredword.at(i) == 'u' || enteredword.at(i) == 'A' || enteredword.at(i) == 'E' || enteredword.at(i) == 'I' || enteredword.at(i) == 'O' || 
             enteredword.at(i) == 'U')
         
            {
                 enteredword.erase(i, 1);
                i == 0;
             }
          
         }
    }

  11. #11
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    What is line 36 supposed to be doing?

  12. #12
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    If it does find a vowel it resets i to 0 so it starts the search over because the position of the letters will be messed up.

  13. #13
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    See post #7.

  14. #14
    C++ Witch laserlight's Avatar
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    Are you sure that it resets i to 0?
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  15. #15
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    wow guys... I realize how stupid I am. So when i want something to literally equal 0 i do one and when i want it to emulate something its two equal signs? btw the code works perfectly, thanks so much for the help.

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