Question

All I want to do is to check whether an element exists in the vector or not, so I can deal with each case.

if ( item_present )    do_this(); else    do_that(); 

Answer 1

You can use std::find from <algorithm>:

#include <algorithm> #include <vector> vector<int> vec;  //can have other data types instead of int but must same datatype as item  std::find(vec.begin(), vec.end(), item) != vec.end() 

This returns an iterator to the first element found. If not present, it returns an iterator to one-past-the-end. With your example:

#include <algorithm> #include <vector>  if ( std::find(vec.begin(), vec.end(), item) != vec.end() )    do_this(); else    do_that();