C++ 标准模板库 (STL) 中的多重集
在本教程中,我们将讨论一个程序来了解 C++ STL(标准模板库)中的多重集。
多重集是与集合非常相似的关联容器。多重集具有的一个区别是它们甚至可以包含重复的值。
示例
#include <iostream> #include <set> #include <iterator> using namespace std; int main(){ multiset <int, greater <int> > gquiz1; //inserting values gquiz1.insert(40); gquiz1.insert(30); gquiz1.insert(60); gquiz1.insert(20); gquiz1.insert(50); gquiz1.insert(50); gquiz1.insert(10); multiset <int, greater <int> > :: iterator itr; cout << "\nThe multiset gquiz1 is : "; for (itr = gquiz1.begin(); itr != gquiz1.end(); ++itr) { cout << '\t' << *itr; } cout << endl; multiset <int> gquiz2(gquiz1.begin(), gquiz1.end()); cout << "\nThe multiset gquiz2 after assign from gquiz1 is : "; for (itr = gquiz2.begin(); itr != gquiz2.end(); ++itr) { cout << '\t' << *itr; } cout << endl; cout << "\ngquiz2 after removal of elements less than 30 : "; gquiz2.erase(gquiz2.begin(), gquiz2.find(30)); for (itr = gquiz2.begin(); itr != gquiz2.end(); ++itr) { cout << '\t' << *itr; } int num; num = gquiz2.erase(50); cout << "\ngquiz2.erase(50) : "; cout << num << " removed \t" ; for (itr = gquiz2.begin(); itr != gquiz2.end(); ++itr) { cout << '\t' << *itr; } cout << endl; cout << "gquiz1.lower_bound(40) : "<< *gquiz1.lower_bound(40) << endl; cout << "gquiz1.upper_bound(40) : "<< *gquiz1.upper_bound(40) << endl; cout << "gquiz2.lower_bound(40) : "<< *gquiz2.lower_bound(40) << endl; cout << "gquiz2.upper_bound(40) : "<< *gquiz2.upper_bound(40) << endl; return 0; }
输出
The multiset gquiz1 is : 60505040302010 The multiset gquiz2 after assign from gquiz1 is : 10203040505060 gquiz2 after removal of elements less than 30 : 3040505060 gquiz2.erase(50) : 2 removed 304060 gquiz1.lower_bound(40) : 40 gquiz1.upper_bound(40) : 30 gquiz2.lower_bound(40) : 40 gquiz2.upper_bound(40) : 60
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