Deleting an element from a vector

This is a discussion on Deleting an element from a vector within the C++ Programming forums, part of the General Programming Boards category; I'v echecked before how to delete a vector entry, but that was to go through the whole vector one element ...

  1. #1
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    Deleting an element from a vector

    I'v echecked before how to delete a vector entry, but that was to go through the whole vector one element at a time. I was wandering if I can erase the last vector entry if it's equal to something in particular.
    I'm trying this:
    Code:
              if(strncmp(SAD.vectDL[SAD.vectDL.size() - 1].Param, "ENDL", 4) == 0)
    			{
    				iterator = vars.vectParmSelectedS.begin();
    
    				while(iterator != vars.vectParmSelectedS.end())     
    				{
    					if(strncmp(SAD.vectDL[SAD.vectDL.size() - 1].Param, "ENDL", 4) == 0)
    						iterator = vars.vectParmSelectedS.erase(iterator);
    					else
    						++iterator;
    
    				}
    			}
    So if the last entry in the vector is "ENDL" I want to delete it. In this case I got hrough the whole vector looking for that entry again.
    There must be a less painful way to delete an entry. Ex: can I use the index of the last entry somehow?
    to avoid doing all of this, is there a swap function that I can use to swap the last entry with another on in the vector?
    Everything is relative...

  2. #2
    C++ Witch laserlight's Avatar
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    Take a look at back() and pop_back().
    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

  3. #3
    Senior Member joshdick's Avatar
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    Code:
    vector<T> v;
    T target;
    
    if(v.back() == target)
    {
         v.erase(v.back(), v.end());
         // or simply v.erase(v.back());
    }
    Does that work for you?
    FAQ

    "The computer programmer is a creator of universes for which he alone is responsible. Universes of virtually unlimited complexity can be created in the form of computer programs." -- Joseph Weizenbaum.

    "If you cannot grok the overall structure of a program while taking a shower, you are not ready to code it." -- Richard Pattis.

  4. #4
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    I actually thought it would be safer to delete all instances of that entry so I used:
    Code:
    vector <DataLine>::iterator iterator1 = SAD.vectDL.begin();
    
    	while(iterator1 != SAD.vectDL.end())     
    	{
    		if(iterator1->Param == "ENDL")
    			iterator1 = SAD.vectDL.erase(iterator1);
    		else
    			++iterator1;
    
    	}
    but pop-back is very suefull.

    Thanks,

    AS.
    Everything is relative...

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