I'm trying to resize a forward list without using the resize() method

user_17587046 0
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I want to try reversing a forward_list (without the reverse() method) but I'm not sure how to get rid of the last element after the erase_after() method without using resize().

#include<forward_list>  

template<typename vt>
class reverse_forward_list{
public:
    static void reverse(std::forward_list<vt>& list){
        
        typename std::forward_list<vt>::iterator iter = list.begin();
        int x = 0;
        for(vt& i :list){
            list.emplace_front(i);
            
            x++;
        }
        list.erase_after(iter,list.end());
        
        //list.resize(x);
    }
};

Any help is appreciated

reverse data-structures stl c++
2 Answers

Use list.before_begin() instead to also erase the previous first element.

Also, this can be implemented more efficiently by splicing each node to the front of the list (which is probably how reverse works internally, and you won't have to allocate new nodes/construct new values)

user_57546560

IMHO there should be a VERY good reason for manipulating a list while traversing it... It's a disaster waiting to happen.

Instead, consider using a temporary list, something like that:

template<typename vt>
static void reverse(std::forward_list<vt>& list) {
  std::forward_list<vt> newlist;
  while (!list.empty()) {
    newlist.push_front(list.front());
    list.pop_front();
  }
  list = newlist;
}
user_10304100
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