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how to check a value exists in a c   stl vector and apply a function to every element of the vector?
#include <vector>
#include <algorithm>

class apply_me
{
  int multiplicator_;
  public:
  apply_me(const int multiplicator) : multiplicator_(multiplicator)
  {};
  int operator ()(const int element) const
  {
    return element*multiplicator_;
  };
};
int main()
{
  std::vector<int> v;
  std::transform(v.begin(), v.end(),v.begin(), apply_me(3));
}