conditional push_back

[gelbeiche]

I have a std::list and I want extend the content of
the list (append a value) only if the value not
already exist.
E.g. I can write for a std::list<int> :

A)
if ( std::find(l.begin(),l.end(), 3) == l.end() )
l.insert(l.end(),3);

or

B)
if ( std::find(l.begin(),l.end(), 3) == l.end() )
l.push_back(3);

I have two questions:
1) Is there a better respectively shorter way to
express this ?
2) Which of both inserts (A or B) is the better one ?

 

[Siemel Naran]

I have a std::list and I want extend the content of
the list (append a value) only if the value not
already exist.
E.g. I can write for a std::list<int> :

A)
if ( std::find(l.begin(),l.end(), 3) == l.end() )
l.insert(l.end(),3);

or

B)
if ( std::find(l.begin(),l.end(), 3) == l.end() )
l.push_back(3);

I have two questions:
1) Is there a better respectively shorter way to
express this ?
2) Which of both inserts (A or B) is the better one ?

1) Would a std::set<int> be what you want?
2) They're probably the same.