C++에서 LRU 캐시를 구현해야합니다. 이 코드를 가지고 컴파일하는 동안 나는 문제가있다 :C++에서 LRU 캐시 구현 - 컴파일 오류
#include <iostream>
#include <vector>
#include <hash_map>
using namespace std;
using namespace stdext;
template<class K, class T>
struct LRUCacheEntry
{
K key;
T data;
LRUCacheEntry* prev;
LRUCacheEntry* next;
};
template<class K, class T>
class LRUCache
{
private:
hash_map< K, LRUCacheEntry<K,T>* > _mapping;
vector< LRUCacheEntry<K,T>* > _freeEntries;
LRUCacheEntry<K,T> * head;
LRUCacheEntry<K,T> * tail;
LRUCacheEntry<K,T> * entries;
public:
LRUCache(size_t size){
entries = new LRUCacheEntry<K,T>[size];
for (int i=0; i<size; i++)
_freeEntries.push_back(entries+i);
head = new LRUCacheEntry<K,T>;
tail = new LRUCacheEntry<K,T>;
head->prev = NULL;
head->next = tail;
tail->next = NULL;
tail->prev = head;
}
~LRUCache()
{
delete head;
delete tail;
delete [] entries;
}
void put(K key, T data)
{
LRUCacheEntry<K,T>* node = _mapping[key];
if(node)
{
// refresh the link list
detach(node);
node->data = data;
attach(node);
}
else{
if (_freeEntries.empty())
{
node = tail->prev;
detach(node);
_mapping.erase(node->key);
node->data = data;
node->key = key;
attach(node);
}
else{
node = _freeEntries.back();
_freeEntries.pop_back();
node->key = key;
node->data = data;
_mapping[key] = node;
attach(node);
}
}
}
T get(K key)
{
LRUCacheEntry<K,T>* node = _mapping[key];
if(node)
{
detach(node);
attach(node);
return node->data;
}
else return NULL;
}
private:
void detach(LRUCacheEntry<K,T>* node)
{
node->prev->next = node->next;
node->next->prev = node->prev;
}
void attach(LRUCacheEntry<K,T>* node)
{
node->next = head->next;
node->prev = head;
head->next = node;
node->next->prev = node;
}
};
컴파일 resualt :
이In file included from /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/backward/hash_map:60,
from Source.C:3:
/usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/backward/backward_warning.h:28:2: warning: #warning This file includes at least one deprecated or antiquated header which may be removed without further notice at a future date. Please use a non-deprecated interface with equivalent functionality instead. For a listing of replacement headers and interfaces, consult the file backward_warning.h. To disable this warning use -Wno-deprecated.
Source.C:6: error: âstdextâ is not a namespace-name
Source.C:6: error: expected namespace-name before â;â token
Source.C:21: error: ISO C++ forbids declaration of âhash_mapâ with no type
Source.C:21: error: expected â;â before â<â token
Source.C: In member function âvoid LRUCache<K, T>::put(K, T)â:
Source.C:46: error: â_mappingâ was not declared in this scope
Source.C: In member function âT LRUCache<K, T>::get(K)â:
Source.C:77: error: â_mappingâ was not declared in this scope
누군가가 내가 "stdext"문제를 해결할 수있는 방법을 말해 줄 수 있습니까? 난 나머지 오류를 해결할 것 같아요. TNX!
3/5 규칙을 따르지 않고 C++ 11로 업그레이드하면'std :: unordered_map'을 사용할 수 있습니다. ** 헤더에'namespace blah;를 사용하지 마십시오. 'put '과'get'는'operator []'의 일반적인 맵 인터페이스로 대체하는 것이 더 나을 것입니다. – chris
@chris가 말한 것에 더하여, 헤더 파일에'using namespace ... '문을 추가하는 것을 삼가하십시오. 약간 짜증나지만 템플릿 코드에서 네임 스페이스를 사용하면 클래스 이름 충돌을 피할 수 있습니다. –