vector_pro::find

C++

size_type find(const value_type& target, int(compare2)(const value_type &, const value_type &), size_type from = 0, size_type exclude_to = -1) const;
size_type find(const value_type& target, size_type from = 0, size_type exclude_to = -1) const;

iterator_pro<value_type> find(const value_type& target, int(compare2)(const value_type &, const value_type &), iterator_pro<value_type> from, iterator_pro<value_type> exclude_to) const;
iterator_pro<value_type> find(const value_type& target, iterator_pro<value_type> from, iterator_pro<value_type> exclude_to) const;

const_iterator_pro<value_type> find(const value_type& target, int(compare2)(const value_type &, const value_type &), const_iterator_pro<value_type> from, const_iterator_pro<value_type> exclude_to) const;
const_iterator_pro<value_type> find(const value_type& target, const_iterator_pro<value_type> from, const_iterator_pro<value_type> exclude_to) const;

Find an element

Returns the position of the first element which is equal to the target .

Please note that you must ensure your value_type implements the == comparison operator, or you must pass a function of the type int(const value_type &, const value_type &) as a parameter.

Also note that calling the function by passing illegal from or exclude_to will get an exception.

Parameters

1. target
   The target value you are going to find.
2. from , exclude_to
   The range of elements we are find the target.
   Can be size_type / iterator_pro / const_iterator_pro .
   If the types are szie_types , the params have default values 0 (start of the container) and -1 (end of the container).
   The range includes all the elements between from and exclude_to, including the element pointed by from but not the one pointed by exclude_to.
3. int(compare2)(const value_type &, const value_type &)
   To let us understand how to compare two value_type.

Return value

The position of the first element which is equal to the target .

The type will be same as the params. ( size_type / iterator_pro / const_iterator_pro )

If nothing found, -1 ( size_type ) or the exclude_end ( iterator_pro / const_iterator_pro ) will be returned.

Example

C++

// vector_pro::find
#include <iostream>
#include "vector_pro.h"

/**
 * Output:
 * (1) the nearest 9 is at:: 8
 * (2) the nearest 9 is at:: 11
 */

int main ()
{
  vector_pro<int> myvector;

  // set some values (from 1 to 10)
  for (int i=1; i<=10; i++) myvector.push_back(i);
  for (int i=10; i>=0; i--) myvector.push_back(i);

  // find the element 9 from the begin of container
  auto idx = myvector.find (9, myvector.begin(), myvector.end());
  std::cout << "(1) the nearest 9 is at:: " << idx.get_idx() << "\n";

  // find the element 9 reversely from the end of container
  auto idx2 = myvector.find (9, myvector.rbegin(), myvector.rend());
  std::cout << "(2) the nearest 9 is at:: " << idx2.get_idx() << "\n";

  return 0;
}

Complexity

Linear on the number of elements in the range.