set的使用

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原创最新推荐文章于 2026-08-30 16:00:42 发布 420 阅读 AI 写同款· GEO 优化 ›

C++中set的使用 • set的声明如下，T就是set底层关键字的类型• set默认要求T⽀持⼩于⽐较，如果不⽀持或者想按⾃⼰的需求⾛可以⾃⾏实现仿函数传给第⼆个模版参数• set底层存储数据的内存是从空间配置器申请的，如果需要可以⾃⼰实现内存池，传给第三个参数。• ⼀般情况下，我们都不需要传后两个模版参数。• set底层是⽤红⿊树实现，增删查效率是 O(logN) ，迭代器遍历是⾛的搜索树的中序，所以是有序的。阅读详情

#include <stdio.h>
#include <stdlib.h>
#include <set>
#include <iostream>
#include <functional>
#include <algorithm>
using namespace std;
struct ltstr{  bool operator()(const char* s1, const char* s2) const { return strcmp(s1, s2) < 0;}};
int main()
{
  const int N = 6;
  const char* a[N] = {"isomer", "ephemeral", "prosaic", "nugatory", "artichoke", "serif"};
  const char* b[N] = {"flat", "this", "artichoke","frigate", "prosaic", "isomer"};
  set<const char*, ltstr> A(a, a + N);
  set<const char*, ltstr> B(b, b + N);
  set<const char*, ltstr> C;
  cout << "Set A: ";
  copy(A.begin(), A.end(), ostream_iterator<const char*>(cout, " "));
  cout << endl;
  cout << "Set B: ";
  copy(B.begin(), B.end(), ostream_iterator<const char*>(cout, " "));
  cout << endl;
  cout << "Union: ";
  set_union(A.begin(), A.end(), B.begin(), B.end(),ostream_iterator<const char*>(cout, " "),ltstr());

cout << endl;
  cout << "Intersection: ";
  set_intersection(A.begin(), A.end(), B.begin(), B.end(),ostream_iterator<const char*>(cout, " "),ltstr());
  cout << endl;
  set_difference(A.begin(), A.end(), B.begin(), B.end(),inserter(C, C.begin()),ltstr());
  cout << "Set C (difference of A and B): ";
  copy(C.begin(), C.end(), ostream_iterator<const char*>(cout, " "));
  cout << endl;
}