mismatch(3C++) - mismatch(3C++)
Standard C++ Library Copyright 1998, Rogue Wave Software, Inc.
NAMEmismatch
- Compares elements from two sequences and returns the first two ele‐
ments that don't match each other.
SYNOPSIS
#include <algorithm>
template <class InputIterator1, class InputIterator2>
pair<InputIterator1,InputIterator2>
mismatch(InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2);
template <;class InputIterator1, class InputIterator2,
class BinaryPredicate>
pair<InputIterator1, Inputiterator2>
mismatch(InputIterator first1, InputIterator1 last1,
InputIterator2 first2,
BinaryPredicate binary_pred);
DESCRIPTION
The mismatch algorithm compares members of two sequences and returns
two iterators (i and j) that point to the first location in each
sequence where the sequences differ from each other. Notice that the
algorithm denotes both a starting position and an ending position for
the first sequence, but denotes only a starting position for the second
sequence. mismatch assumes that the second sequence has at least as
many members as the first sequence. If the two sequences are identical,
mismatch returns a pair of iterators that point to the end of the first
sequence and the corresponding location at which the comparison stopped
in the second sequence.
The first version of mismatch checks members of a sequence for equal‐
ity, while the second version lets you specify a comparison function.
The comparison function must be a binary predicate.
The iterators i and j returned by mismatch are defined as follows:
j == first2 + (i - first1)
and i is the first iterator in the range [first1, last1) for which the appro‐
priate one of the following conditions hold:
!(*i == *(first2 + (i - first1)))
orbinary_pred(*i, *(first2 + (i - first1))) == false
If all of the members in the two sequences match, mismatch returns a pair of
last1 and first2 + (last1 - first1).
COMPLEXITY
At most last1 - first1 applications of the corresponding predicate are
done.
EXAMPLE
//
// mismatch.cpp
//
#include <algorithm>
#include <vector>
#include <iostream>
using namespace std;
int main(void)
{
typedef vector<int>::iterator iterator;
int d1[4] = {1,2,3,4};
int d2[4] = {1,3,2,4};
// Set up two vectors
vector<int> vi1(d1,d1 + 4), vi2(d2,d2 + 4);
// p1 will contain two iterators that point to the
// first pair of elements that are different between
// the two vectors
pair<iterator, iterator> p1 = mismatch(vi1.begin(),
vi1.end(),vi2.begin());
// find the first two elements such that an element in
// the first vector is greater than the element in
// the second vector.
pair<iterator, iterator> p2 = mismatch(vi1.begin(),
vi1.end(), vi2.begin(),
less_equal<int>());
// Output results
cout << *p1.first << ", " << *p1.second << endl;
cout << *p2.first << ", " << *p2.second << endl;
return 0;
}
Program Output2, 3
3, 2
WARNINGS
If your compiler does not support default template parameters, then you
always need to supply the Allocator template argument. For instance,
you need to write:
vector<int, allocator<int> >
instead of:
vector<int>
If your compiler does not support namespaces, then you do not need the
using declaration for std.
Rogue Wave Software 02 Apr 1998 mismatch(3C++)
