c++stl

How do you determine the last valid element in a STL-Container

If i iterate over a STL container i sometimes need to know if the current item is the last one in the sequence. Is there a better way, then doing something like this? Can i somehow convert rbegin()?

std::vector<int> myList;

// ....
std::vector<int>::iterator lastit = myList.end();  
lastit--;

for(std::vector<int>::iterator it = myList.begin(); it != myList.end(); it++)  {
     if(it == lastit)
     {
        // Do something with last element
     }
     else
     {
       //  Do something with all other elements
     }
Solution

  • Try the following

    std::vector<int>::iterator it2 = (++it);
if ( it2 == myList.end() ) {
  ...
}

    The following should work as well

    if ( it+1 == myList.end() ) {
  // it is last
  ...
}