Question

Coming from Java and using the ArrayList class has me all frustrated when trying to learn the C++ equivalent (Vectors).

I’m writing a function that removes a certain int given from a vector of ints. For awhile I could not figure out why it was causing a segmentation fault. After looking at the documentation I realized .erase also removes any element after the one being erased. Which is definitely not what I want to do, so I’m a little lost of how I would go about removing only a single element from a vector without removing the elements after.

Function that I currently have which causes a segmentation fault:

void remove(int n){

    for(int a=0; a<list.size(); a++){

        if(list.at(a)==n){
            list.erase (list.begin()+(n-1));
            cout << n << " has been erased" << endl;
            break;
        }
    }
}

Answer 1

You’re looking for n as an element, but are also using it as an index. I don’t think this is what you want.

If you replace (n-1) by a, it should work:

        list.erase(list.begin()+a);

Alternative way to remove a single element, using find and erase:

#include <algorithm>
//...
void removeOne(int n){
    vector<int>::iterator found = std::find(list.begin(), list.end(), n) ;
    if (found!=list.end())
        list.erase(found);
}