STL hash_map

来源：互联网发布：unity3d save project 编辑：程序博客网时间：2024/09/21 08:19

定义哈希函数和比较函数

#include <hash_map> #include <string> #include <iostream>  using namespace std;  //define the class struct ClassA {     ClassA(int a):c_a(a){}     int getvalue()const { return c_a;}     size_t c_a;      }; //1 define the hash function struct hash_A {      enum        {   //   parameters   for   hash   table           bucket_size  =2 ,         min_buckets   =4     };        size_t operator()(const class ClassA & A)const     {          return  A.getvalue()%min_buckets;     }  //2 define the equal function      bool operator()(const class ClassA & a1, const class ClassA & a2)const     {          return a1.getvalue()<a2.getvalue();     }  };  int main()  {      hash_map<ClassA,string, hash_A> hmap;      ClassA a1(2);      hmap[a1]="I love C++";      ClassA a2(56);      hmap[a2]="Do you love it?";      cout<<hmap[a1]<<endl;      cout<<hmap[a2]<<endl;      return 0;  }

0 0