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按年龄比较Person的大小，直接上代码。
方式一（适用于自定义类型）：
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 | #include <iostream> #include <string> #include <map> using namespace std; struct Person { Person(string name, int age) { this ->name = name; this ->age = age; } string name; int age; bool operator < ( const Person &p1) const { return this ->age < p1.age; } }; int main() { map<Person, string> mm = { {Person( "Alice" , 34), "girl" }, {Person( "Tom" , 23), "boy" }, {Person( "Joey" , 45), "boy" } }; for ( const auto &p : mm) { cout << p.first.name << " * " << p.first.age << " * " << p.second << endl; } return 0; } |
方式二（适用于不可控的类型）：
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 | #include <iostream> #include <string> #include <map> using namespace std; struct Person { Person(string name, int age) { this ->name = name; this ->age = age; } string name; int age; }; struct ltPerson { bool operator()( const Person &p1, const Person &p2) const { return p1.age < p2.age; } }; int main() { map<Person, string, ltPerson> mm = { {Person( "Alice" , 34), "girl" }, {Person( "Tom" , 23), "boy" }, {Person( "Joey" , 45), "boy" } }; for ( const auto &p : mm) { cout << p.first.name << " * " << p.first.age << " * " << p.second << endl; } return 0; } |
运行截图：
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