sort（）
声明
template <class RandomAccessIterator, class Compare>
void sort (RandomAccessIterator first, RandomAccessIterator last, Compare comp);
示例
1 // sort algorithm example
2 #include <iostream>
3 #include <algorithm>
4 #include <vector>
5 #include <string>
6
7
8 using namespace std;
9
10 // 定义结构体
11 struct student
12 {
13 int age;
14 string name;
15 student(int a, string s)
16 {
17 age = a;
18 name = s;
19 }
20 };
21
22
23 // 自定义比较函数
24 bool myfunction(int i, int j) {
25 return (i < j);
26 }
27
28
29 //重载运算符 注意参数类型要求
30 bool operator<(const student s1, const student s2)
31 {
32 if (s1.age == s2.age)
33 return s1.name < s2.name;//年龄相同时，按姓名小到大排
34 else
35 return s1.age < s2.age; //从年龄小到大排序
36 }
37
38
39 // 声明比较类
40 struct cmp
41 {
42 bool operator() (const student& s1, const student& s2)
43 {
44 if (s1.age == s2.age)
45 return s1.name < s2.name;
46 else return s1.age < s2.age;
47 }
48 }mycmp;
49
50 struct cmp2
51 {
52 bool operator() (int a, int b)
53 {
54 return a < b;
55 }
56 }mycmp2;
57
58
59 int main() {
60 vector<int> vec = { 32,71,12,45,26,80,53,33 };
61
62
63 // 使用默认比较器 (operator <):
64 sort(vec.begin(), vec.end()); //12 26 32 33 45 53 71 80
65
66 // 自定义比较函数（函数指针）
67 sort(vec.begin() + 4, vec.end(), myfunction); // 12 32 45 71(26 33 53 80)
68
69 // 重载比较运算符
70 student s1(10, "wangwu");
71 student s2(10, "lisi");
72 student s3(12, "zhangsan");
73 vector<student> s = { s1, s2, s3 };
74 //sort(s.begin(), s.end()); //s2 s1 s3
75
76
77 // 声明比较类
78 // 注意二者写法的区别
79 sort(s.begin(), s.end(), cmp()); //s2 s1 s3
80 sort(s.begin(), s.end(), mycmp); //s2 s1 s3
81
82 sort(vec.begin(), vec.end(), cmp2()); //12 26 32 33 45 53 71 80
83 sort(vec.begin(), vec.end(), mycmp2); //12 26 32 33 45 53 71 80
84
85 // 使用匿名函数
86 sort(vec.begin(), vec.end(), [](int a, int b) {return a < b; }); //12 26 32 33 45 53 71 80
87
88 system("pause");
89 return 0;
90 }
priority_queue
声明
template <class T, class Container = vector<T>,
class Compare = less<typename Container::value_type> > class priority_queue;
示例
1 #include<iostream>
2 #include<queue>
3 #include<vector>
4 #include <functional>
5
6 using namespace std;
7
8 template<typename T> void print_queue(T& q) {
9 while (!q.empty()) {
10 cout << q.top() << " ";
11 q.pop();
12 }
13 cout << endl;;
14 }
15
16 // 声明比较类
17 struct comp
18 {
19 bool operator()(int in1, int in2) const
20 {
21 return (in1>in2);
22 }
23 };
24
25
26 int main()
27 {
28 vector<int> v = { 1,3,5,7,9,2,4,6,8,10 };
29 priority_queue<int> q1;
30 for (auto c : v)
31 {
32 q1.push(c);
33 }
34 print_queue(q1);
35
36 priority_queue<int, vector<int>, greater<int> > q2;
37 for (auto c : v)
38 {
39 q2.push(c);
40 }
41 print_queue(q2);
42
43 // 使用匿名函数
44 auto cmp = [](int a, int b) { return a < b; };
45 priority_queue<int, vector<int>, decltype(cmp)> q3(cmp);
46 for (auto c : v)
47 {
48 q3.push(c);
49 }
50 print_queue(q3);
51
52 int a = 4;
53
54 // 声明比较类
55 priority_queue<int, vector<int>, comp> q4;
56 for (auto c : v)
57 {
58 q4.push(c);
59 }
60 print_queue(q4);
61
62
63 cout << "\n" << endl;
64 system("pause");
65 return 0;
66 }
