adjacent_find « STL Algorithms Non modifying sequence operations « C++ Tutorial

25.1.1.adjacent_find: search first two elements with equal value
25.1.2.Illustrating the generic adjacent_find algorithm
25.1.3.adjacent_find: search first two elements for which the second has double the value of the first
25.1.4.Use generic adjacent_find algorithm with a predicate to find the first name that is lexicographically greater than the next one