Question

Have a look at this snippet:

#include <string>
#include <iostream>
#include <vector>

using namespace std;

class base {
public:
  string foo;
  base() {};
  base(const base &orig) {
    this->foo = orig.foo;
  };
 ~base() {} ;
};

class derived : public base {
public:
  string bar;
  derived(const derived &orig) : base(orig) {
    this->bar = orig.bar;
  }
  derived() : base() {} ;
  ~derived() {};
};

void asd(derived d)
{
    // works fine
    cout << d.foo << d.bar << endl;
}

int main(void)
{
    vector<derived> v;

    derived bla;

    bla.foo = "Test ";
    bla.bar = "String ";

    v.push_back(bla);

    asd(bla);

    // Why the hell does v.end()->foo and v.end()->bar segfault?!
    cout << v.end()->foo;
    cout << v.end()->bar << endl;
}

Why do I get an segmentation fault? This is the console output
(compiled with g++ -o test test.cpp -g)

./test
Test String 
zsh: segmentation fault  ./test

The this pointer of the class derived v.end() does not point to the correct position…
But why?

Answer 1

end() is not an iterator pointing to the last element. It points to one past the last element. Dereferencing end() is illegal.

Use back() if you want the last element.