std::map find 自定義類型元素

1、定義結構體

struct StructStu
{
	int _num1;
	int _num2;
	int _num3;

	StructStu(int num1,int num2,int num3)
	{
		_num1 = num1;
		_num2 = num2;
		_num3 = num3;
	}
};
           

2、書寫自定義類型的運算符函數

class StructStuCmp
{
public:
	bool operator() (const StructStu &left ,const StructStu& right) const
	{
		if(left._num1 != right._num1)
			return left._num1 < right._num1;
		if(left._num2 != right._num2)
			return left._num2 < right._num2;
		if(left._num3 != right._num3)
			return left._num3 < right._num3;
		return false;
	}
};
           

3、測試使用

std::map<StructStu ,std::string ,StructStuCmp> StuStrMap;
	StructStu stu1(1,2,3);
	StructStu stu2(2,3,4);
	StructStu stu3(3,4,5);
	StuStrMap.insert(make_pair(stu1,std::string("test1")));

	auto strMap = StuStrMap.find(stu1);
	if(strMap != StuStrMap.end())
	{
		StructStu stuTest = strMap->first;
		std::string str = strMap->second;
		cout<<stuTest._num1<<endl;
		cout<<stuTest._num2<<endl;
		cout<<stuTest._num3<<endl;
		cout<<str<<endl;
	}else
	{
		cout<<"error"<<endl;
	}