C++ Tutorial/STL Algorithms Min Max/min element
Содержание
Find and print minimum elements in a vector
<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 <algorithm>
using namespace std; int main() {
vector<int> coll; vector<int>::iterator pos; // insert elements from 1 to 6 in arbitrary order coll.push_back(2); coll.push_back(5); coll.push_back(4); coll.push_back(1); coll.push_back(6); coll.push_back(3); // find and print minimum elements pos = min_element (coll.begin(), coll.end()); cout << "min: " << *pos << endl;
}</source>
min: 1
Use min_element to get the minimum element in a container
<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 <cstdlib>
- 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() {
deque<int> coll; INSERT_ELEMENTS(coll,2,8); INSERT_ELEMENTS(coll,-3,5); PRINT_ELEMENTS(coll); // process and print minimum cout << "minimum: " << *min_element(coll.begin(),coll.end()) << endl;
}</source>
2 3 4 5 6 7 8 -3 -2 -1 0 1 2 3 4 5 minimum: -3
Use min_element to get the minimum value
<source lang="cpp">#include <algorithm>
- include <functional>
- include <iomanip>
- include <iostream>
- include <vector>
using namespace std; int main(){
const float a[] = { 13.4, 27.6, 15.5, 44.3, 51.2, 30.2, 18.0 }; vector<float> data( a,a + sizeof( a ) / sizeof( a[0] ) ); float data_min = *min_element( data.begin(), data.end() ); cout << data_min;
}</source>
Use min_element with criteria 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 <cstdlib>
- 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;
bool absLess (int elem1, int elem2) {
return abs(elem1) < abs(elem2);
}
int main() {
deque<int> coll; INSERT_ELEMENTS(coll,2,8); INSERT_ELEMENTS(coll,-3,5); PRINT_ELEMENTS(coll); cout << "minimum of absolute values: " << *min_element(coll.begin(),coll.end(), absLess) << endl;
}</source>
2 3 4 5 6 7 8 -3 -2 -1 0 1 2 3 4 5 minimum of absolute values: 0