check if a std vector contains a certain object

Question

Is there something in  lt algorithm gt  which allows  you to check if a std   container contains something  Or  a way to make one  for example   if a x    b x  amp  amp  a y    b y  return true   return false    Can this only be done with std  map since it uses keys   Thanks

User · Answer

See question  How to find an item in a std  vector   You ll also need to ensure you ve implemented  a suitable operator     for your object  if the default one isn t sufficient for a  deep  equality test

User · Answer

If searching for an element is important  I d recommend std  set instead of std  vector   Using this   std  find vec begin    vec end    x  runs in O n  time  but std  set has its own find   member  ie  myset find x   which runs in O log n  time - that s much more efficient with large numbers of elements  std  set also guarantees all the added elements are unique  which saves you from having to do anything like if not contained then push back

User · Answer

Checking if v contains the element x    include  lt algorithm gt   if std  find v begin    v end    x     v end             v contains x      else          v does not contain x        Checking if v contains elements  is non-empty    if  v empty            v is non-empty      else          v is empty

[c++] check if a std::vector contains a certain object?

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