find

     Algorithm

Find an occurence of value in a sequence

Contents

• Synopsis
• Description
• Complexity
• Example
• Warning
• See Also

#include <algorithm>

template <class InputIterator, class T>
  InputIterator find(InputIterator first, InputIterator last,
                     const T& value);

The find algorithm lets you search for the first occurence of a particular value in a sequence. find returns the first iterator i in the range [first, last) for which the following condition holds:

*i == value.  

If find does not find a match for value, it returns the iterator last.

find peforms at most last-first comparisons.

//
// find.cpp
//
 #include <vector>
 #include <algorithm>
 int main()
 {
   typedef vector<int>::iterator iterator;
   int d1[10] = {0,1,2,2,3,4,2,2,6,7}; 
   // Set up a vector
   vector<int> v1(d1,d1 + 10);
   // Try find  
   iterator it1 = find(v1.begin(),v1.end(),3);
   // it1 = v1.begin() + 4;
   // Try find_if
   iterator it2 = 
      find_if(v1.begin(),v1.end(),bind1st(equal_to<int>(),3));
   // it2 = v1.begin() + 4
   // Try both adjacent_find variants
   iterator it3 = adjacent_find(v1.begin(),v1.end());
   // it3 = v1.begin() +2
   iterator it4 = 
      adjacent_find(v1.begin(),v1.end(),equal_to<int>());
   // v4 = v1.begin() + 2
   // Output results
   cout << *it1 << " " << *it2 << " " << *it3 << " " 
        << *it4 << endl;
   return 0;
 }
Output : 3 3 2 2

If your compiler does not support default template parameters then you need to always supply the Allocator template argument. For instance you'll have to write:

vector<int,allocator>

instead of:

vector<int>

adjacent_find, find_first_of, find_if