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Create OS Page Replacement Algorithms in C++ tarunsinghofficial#2645
OS Page Replacement Algorithms in C++ tarunsinghofficial#2645 1.FIFO (First-In-First-Out) Page Replacement Algorithm in C++ 2.LRU (Least Recently Used) Page Replacement Algorithm in C++
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OS Page Replacement Algorithms in C++ #2645 | ||
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1.FIFO (First-In-First-Out) Page Replacement Algorithm in C++ | ||
#include <iostream> | ||
#include <queue> | ||
#include <unordered_set> | ||
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using namespace std; | ||
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class FIFOPageReplacement { | ||
public: | ||
FIFOPageReplacement(int capacity) { | ||
this->capacity = capacity; | ||
} | ||
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void referencePage(int page) { | ||
if (pageTable.find(page) == pageTable.end()) { | ||
if (pageQueue.size() == capacity) { | ||
int removedPage = pageQueue.front(); | ||
pageQueue.pop(); | ||
pageTable.erase(removedPage); | ||
} | ||
pageQueue.push(page); | ||
pageTable.insert(page); | ||
} | ||
} | ||
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void printPageTable() { | ||
cout << "Page Table: "; | ||
while (!pageQueue.empty()) { | ||
cout << pageQueue.front() << " "; | ||
pageQueue.pop(); | ||
} | ||
cout << endl; | ||
} | ||
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private: | ||
int capacity; | ||
queue<int> pageQueue; | ||
unordered_set<int> pageTable; | ||
}; | ||
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int main() { | ||
int capacity = 3; // Set the capacity of the page table | ||
FIFOPageReplacement fifo(capacity); | ||
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int pages[] = {1, 2, 3, 4, 1, 2, 5}; | ||
int n = sizeof(pages) / sizeof(pages[0]); | ||
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for (int i = 0; i < n; i++) { | ||
fifo.referencePage(pages[i]); | ||
fifo.printPageTable(); | ||
} | ||
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return 0; | ||
} | ||
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2.LRU (Least Recently Used) Page Replacement Algorithm in C++ | ||
#include <iostream> | ||
#include <list> | ||
#include <unordered_map> | ||
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using namespace std; | ||
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class LRUCache { | ||
public: | ||
LRUCache(int capacity) { | ||
this->capacity = capacity; | ||
} | ||
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int get(int key) { | ||
if (cacheMap.find(key) != cacheMap.end()) { | ||
// Move the accessed item to the front | ||
cacheList.splice(cacheList.begin(), cacheList, cacheMap[key]); | ||
return cacheMap[key]->second; | ||
} | ||
return -1; | ||
} | ||
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void put(int key, int value) { | ||
if (cacheMap.find(key) != cacheMap.end()) { | ||
// If the key exists, update its value and move it to the front | ||
cacheMap[key]->second = value; | ||
cacheList.splice(cacheList.begin(), cacheList, cacheMap[key]); | ||
} else { | ||
// If the cache is full, remove the least recently used item | ||
if (cacheList.size() >= capacity) { | ||
int removedKey = cacheList.back().first; | ||
cacheMap.erase(removedKey); | ||
cacheList.pop_back(); | ||
} | ||
// Add the new item to the front | ||
cacheList.push_front({key, value}); | ||
cacheMap[key] = cacheList.begin(); | ||
} | ||
} | ||
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void printCache() { | ||
cout << "LRU Cache: "; | ||
for (auto &entry : cacheList) { | ||
cout << "(" << entry.first << "," << entry.second << ") "; | ||
} | ||
cout << endl; | ||
} | ||
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private: | ||
int capacity; | ||
list<pair<int, int>> cacheList; // List of key-value pairs | ||
unordered_map<int, list<pair<int, int>>::iterator> cacheMap; // Map for quick access to list iterator | ||
}; | ||
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int main() { | ||
int capacity = 3; // Set the capacity of the LRU cache | ||
LRUCache lru(capacity); | ||
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lru.put(1, 1); | ||
lru.printCache(); | ||
lru.put(2, 2); | ||
lru.printCache(); | ||
cout << "Get 1: " << lru.get(1) << endl; // Should print 1 | ||
lru.printCache(); | ||
lru.put(3, 3); | ||
lru.printCache(); | ||
cout << "Get 2: " << lru.get(2) << endl; // Should print 2 | ||
lru.printCache(); | ||
lru.put(4, 4); | ||
lru.printCache(); | ||
cout << "Get 1: " << lru.get(1) << endl; // Should print 1 | ||
lru.printCache(); | ||
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return 0; | ||
} | ||
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