C++ Tutorial/STL Algorithms Non modifying sequence operations/mismatch
Содержание
- 1 Check for mismatch between two vectors
- 2 Demonstrates standard library functions equal, mismatch, lexicographical_compare.
- 3 Generic mismatch algorithm: Find the corresponding positions in a deque and list at which unequal elements first occur
- 4 Use mismatch function to find the first match
- 5 Use mismatch function with custom function
Check for mismatch between two vectors
<source lang="cpp">#include <iostream> using std::cout; using std::endl;
- include <algorithm>
- include <vector>
- include <iterator>
int main() {
int a1[ 10 ] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
int a2[ 10 ] = { 1, 2, 3, 4, 9, 6, 7, 8, 9, 10 };
std::vector< int > v1( a1, a1 + 10 );
std::vector< int > v2( a1, a1 + 10 );
std::vector< int > v3( a2, a2 + 10 );
std::ostream_iterator< int > output( cout, " " );
cout << "Vector v1 contains: ";
std::copy( v1.begin(), v1.end(), output );
cout << "\nVector v2 contains: ";
std::copy( v2.begin(), v2.end(), output );
cout << "\nVector v3 contains: ";
std::copy( v3.begin(), v3.end(), output );
std::pair< std::vector< int >::iterator, std::vector< int >::iterator > location;
location = std::mismatch( v1.begin(), v1.end(), v3.begin() );
cout << "\nThere is a mismatch between v1 and v3 at location "
<< ( location.first - v1.begin() ) << "\nwhere v1 contains "
<< *location.first << " and v3 contains " << *location.second;
return 0;
}</source>
Vector v1 contains: 1 2 3 4 5 6 7 8 9 10 Vector v2 contains: 1 2 3 4 5 6 7 8 9 10 Vector v3 contains: 1 2 3 4 9 6 7 8 9 10 There is a mismatch between v1 and v3 at location 4 where v1 contains 5 and v3 contains 9
Demonstrates standard library functions equal, mismatch, lexicographical_compare.
<source lang="cpp">#include <iostream>
- include <algorithm>
- include <vector>
using namespace std; int main() {
const int SIZE = 10;
int a1[ SIZE ] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
int a2[ SIZE ] = { 1, 2, 3, 4, 1000, 6, 7, 8, 9, 10 };
vector< int > v1( a1, a1 + SIZE ),
v2( a1, a1 + SIZE ),
v3( a2, a2 + SIZE );
bool result = equal( v1.begin(), v1.end(), v2.begin() );
cout << "\n\nVector v1 " << ( result ? "is" : "is not" )
<< " equal to vector v2.\n";
result = equal( v1.begin(), v1.end(), v3.begin() );
cout << "Vector v1 " << ( result ? "is" : "is not" )
<< " equal to vector v3.\n";
pair< vector< int >::iterator,
vector< int >::iterator > location;
location = mismatch( v1.begin(), v1.end(), v3.begin() );
cout << "\nThere is a mismatch between v1 and v3 at "
<< "location " << ( location.first - v1.begin() )
<< "\nwhere v1 contains " << *location.first
<< " and v3 contains " << *location.second
<< "\n\n";
char c1[ SIZE ] = "HELLO", c2[ SIZE ] = "BYE BYE";
result = lexicographical_compare( c1, c1 + SIZE, c2, c2 + SIZE );
cout << c1
<< ( result ? " is less than " : " is greater than " )
<< c2;
cout << endl;
return 0;
}</source>
Generic mismatch algorithm: Find the corresponding positions in a deque and list at which unequal elements first occur
<source lang="cpp">#include <iostream>
- include <cassert>
- include <algorithm>
- include <string>
- include <list>
- include <deque>
- include <vector>
using namespace std; int main() {
list<string> driver_list;
vector<string> vec;
deque<string> deq;
driver_list.insert(driver_list.end(), "AAA");
driver_list.insert(driver_list.end(), "BBBB");
driver_list.insert(driver_list.end(), "CCCCC");
deq.insert(deq.end(), "AAA");
deq.insert(deq.end(), "DDDDDD");
pair<deque<string>::iterator, list<string>::iterator> pair1 = mismatch(deq.begin(), deq.end(),driver_list.begin());
if (pair1.first != deq.end())
cout << "First disagreement in deq and driver_list:\n "
<< *(pair1.first) << " and " << *(pair1.second)
<< endl;
return 0;
}</source>
First disagreement in deq and driver_list: DDDDDD and BBBB
Use mismatch function to find the first match
<source lang="cpp">/* The following code example is taken from the book
* "The C++ Standard Library - A Tutorial and Reference" * by Nicolai M. Josuttis, Addison-Wesley, 1999 * * (C) Copyright Nicolai M. Josuttis 1999. * Permission to copy, use, modify, sell and distribute this software * is granted provided this copyright notice appears in all copies. * This software is provided "as is" without express or implied * warranty, and with no claim as to its suitability for any purpose. */
- include <iostream>
- include <vector>
- include <deque>
- include <list>
- include <set>
- include <map>
- include <string>
- include <algorithm>
- include <iterator>
- include <functional>
- include <numeric>
/* PRINT_ELEMENTS()
* - prints optional C-string optcstr followed by * - all elements of the collection coll * - separated by spaces */
template <class T> inline void PRINT_ELEMENTS (const T& coll, const char* optcstr="") {
typename T::const_iterator pos;
std::cout << optcstr;
for (pos=coll.begin(); pos!=coll.end(); ++pos) {
std::cout << *pos << " ";
}
std::cout << std::endl;
} /* INSERT_ELEMENTS (collection, first, last)
* - fill values from first to last into the collection * - NOTE: NO half-open range */
template <class T> inline void INSERT_ELEMENTS (T& coll, int first, int last) {
for (int i=first; i<=last; ++i) {
coll.insert(coll.end(),i);
}
} using namespace std; int main() {
vector<int> coll1;
list<int> coll2;
INSERT_ELEMENTS(coll1,1,6);
for (int i=1; i<=16; i*=2) {
coll2.push_back(i);
}
coll2.push_back(3);
PRINT_ELEMENTS(coll1,"coll1: ");
PRINT_ELEMENTS(coll2,"coll2: ");
// find first mismatch
pair<vector<int>::iterator,list<int>::iterator> values;
values = mismatch (coll1.begin(), coll1.end(), // first range
coll2.begin()); // second range
if (values.first == coll1.end()) {
cout << "no mismatch" << endl;
}
else {
cout << "first mismatch: "
<< *values.first << " and "
<< *values.second << endl;
}
}</source>
coll1: 1 2 3 4 5 6 coll2: 1 2 4 8 16 3 first mismatch: 3 and 4
Use mismatch function with custom function
<source lang="cpp">/* The following code example is taken from the book
* "The C++ Standard Library - A Tutorial and Reference" * by Nicolai M. Josuttis, Addison-Wesley, 1999 * * (C) Copyright Nicolai M. Josuttis 1999. * Permission to copy, use, modify, sell and distribute this software * is granted provided this copyright notice appears in all copies. * This software is provided "as is" without express or implied * warranty, and with no claim as to its suitability for any purpose. */
- include <iostream>
- include <vector>
- include <deque>
- include <list>
- include <set>
- include <map>
- include <string>
- include <algorithm>
- include <iterator>
- include <functional>
- include <numeric>
/* PRINT_ELEMENTS()
* - prints optional C-string optcstr followed by * - all elements of the collection coll * - separated by spaces */
template <class T> inline void PRINT_ELEMENTS (const T& coll, const char* optcstr="") {
typename T::const_iterator pos;
std::cout << optcstr;
for (pos=coll.begin(); pos!=coll.end(); ++pos) {
std::cout << *pos << " ";
}
std::cout << std::endl;
} /* INSERT_ELEMENTS (collection, first, last)
* - fill values from first to last into the collection * - NOTE: NO half-open range */
template <class T> inline void INSERT_ELEMENTS (T& coll, int first, int last) {
for (int i=first; i<=last; ++i) {
coll.insert(coll.end(),i);
}
} using namespace std; int main() {
vector<int> coll1;
list<int> coll2;
INSERT_ELEMENTS(coll1,1,6);
for (int i=1; i<=16; i*=2) {
coll2.push_back(i);
}
coll2.push_back(3);
PRINT_ELEMENTS(coll1,"coll1: ");
PRINT_ELEMENTS(coll2,"coll2: ");
// find first mismatch
pair<vector<int>::iterator,list<int>::iterator> values;
/* find first position where the element of coll1 is not
* less than the corresponding element of coll2
*/
values = mismatch (coll1.begin(), coll1.end(), // first range
coll2.begin(), // second range
less_equal<int>()); // criterion
if (values.first == coll1.end()) {
cout << "always less-or-equal" << endl;
}
else {
cout << "not less-or-equal: "
<< *values.first << " and "
<< *values.second << endl;
}
}</source>
coll1: 1 2 3 4 5 6 coll2: 1 2 4 8 16 3 not less-or-equal: 6 and 3
