You are provided with a code snippet that manages a cache of memory types. The cache has a fixed number of elements represented by the variable `CACHEELEMS`. The cache is implemented as an array of pointers to objects of type `MemoryType`.

The given code contains two parts. The first part includes a function that adds a memory type to the cache. The second part includes a function that clears the cache.

1. Modify the `void add(const MemoryType& mt)` function to handle the case when the cache is full and there is a memory type with the same value as `mt` already in the cache. If the cache is already full and a new memory type needs to be added, remove the least recently added memory type from the cache. After removing the least recently added memory type, add the new memory type at the end of the cache. Additionally, ensure that the `pos` variable is incremented by 1 (wrapping around if necessary) and store the pointer to the memory type at the corresponding position in the cache array `cache`. Implement this updated function.

2. Modify the `void clear(const MemoryType& mt)` function to handle the case when there are multiple instances of the same memory type in the cache. Instead of setting all elements of the cache array that contain the memory type `mt` to `nullptr`, remove only the first occurrence of `mt` from the cache. Implement this updated function using the `CACHEELEMS`, `CacheIdx`, `pos`, and `cache` variables given in the code snippet.

Additionally, ensure that the `cacheManagement()` function also includes a feature to display the number of occurrences of each memory type in the cache before and after clearing the cache.
user
Sure, I'm happy to help you modify the provided code snippet to include your requested features. Here's how you might do that:

```cpp
// Initialize the cache array and its variables
std::vector<MemoryType*> cache{CACHEELEMS};
std::vector<bool> isCached(CACHEELEMS);
int CacheIdx{0};
int pos{0};

// Function to add a memory type to the cache, handling cache overflow
void add(const MemoryType& mt) {
    // If cache is full
    if (CacheIdx == CACHEELEMS) {
        // Find the least recently added memory type
        int maxPos{0};
        MemoryType* maxMemory{nullptr};
        for (int I{1}; I < CacheIdx; ++i) {
            if (cache[i] != nullptr && cache[maxPos] == nullptr ||
                (cache[i] != nullptr && cache[maxPos] != nullptr && isCached[maxPos])) {
                maxPos = i;
                maxMemory = cache[i];
            }
        }
        // Remove the least recently added memory type
        if (maxMemory != nullptr) {
            cache[maxPos] = nullptr;
            isCached[maxPos] = false;
        }
    }

    // Add the memory type to the cache
    cache[pos] = new MemoryType(mt);
    isCached[pos] = true;

    // Increment the position in the cache
    ++pos;

    // Wrap around if necessary
    if (pos == CACHEELEMS) {
        pos = 0;
    }
}

// Function to clear a memory type from the cache, handling cache duplication
void clear(const MemoryType& mt) {
    // Find the position of the memory type in the cache
    int index{findPosition(mt)};

    // Clear the first occurrence of the memory type from the cache
    if (index >= 0) {
        cache[index] = nullptr;
        isCached[index] = false;
        CacheIdx--;
    }
}

// Helper function to find the position of a memory type in the cache
int findPosition(const MemoryType& mt) const {
    // Loop through the cache
    for (int I{0}; I < CacheIdx; ++i) {
        // Check if the memory type has already been cached
        if (cache[i] != nullptr && cache[i]->mt_ == mt.mt_) {
            return i;
        }
    }

    return -1;
}

// Function to display cache contents
void displayCache() const {
    printf("Cache contents:\n");

    // Print the total number of each memory type cached
    printf("mt_     Occurrences\n");
    for (int I{0}; I < CACHEELEMS; ++i) {
        if (cache[i] != nullptr && isCached[i]) {
            printf("%-10u   %d\n", cache[i]->mt_, countOccurrences(cache[i]->mt_));
        }
    }

    printf("\n");
}

// Helper function to count the number of occurrences of a memory type
int countOccurrences(const MemoryType& mt) const {
    int count{0};

    // Loop through the cache
    for (int I{0}; I < CacheIdx; ++i) {
        // Check if the memory type has already been cached
        if (cache[i] != nullptr && cache[i]->mt_ == mt.mt_) {
            count++;
        }
    }

    return count;
}
```

In this modified code, the `add` function removes the least recently added memory type when the cache is full, and the `clear` function removes only the first occurrence of a memory type. The `displayCache` function and `countOccurrences` helper function print and count the number of each memory type in the cache, respectively.
assistant
You are provided with a code snippet that manages a cache of memory types. The cache has a fixed number of elements represented by the variable `CACHEELEMS`. The cache is implemented as an array of pointers to objects of type `MemoryType`.

The given code contains two parts. The first part includes a function that adds a memory type to the cache. The second part includes a function that clears the cache.

1. Modify the `void add(const MemoryType& mt)` function to handle the case when the cache is full and there is a memory type with the same value as `mt` already in the cache. If the cache is already full and a new memory type needs to be added, remove the least recently added memory type from the cache. After removing the least recently added memory type, add the new memory type at the end of the cache. Additionally, ensure that the `pos` variable is incremented by 1 (wrapping around if necessary) and store the pointer to the memory type at the corresponding position in the cache array `cache`. Implement this updated function.

2. Modify the `void clear(const MemoryType& mt)` function to handle the case when there are multiple instances of the same memory type in the cache. Instead of setting all elements of the cache array that contain the memory type `mt` to `nullptr`, remove only the first occurrence of `mt` from the cache. Implement this updated function using the `CACHEELEMS`, `CacheIdx`, `pos`, and `cache` variables given in the code snippet.

Additionally, ensure that the `cacheManagement()` function also includes a feature to display the number of occurrences of each memory type in the cache before and after clearing the cache.
user
Sure, I can help you modify the functions as per your requirements. Here's how you can do it:

1. For the `add` function, you can use a boolean variable to check if the memory type already exists in the cache. If it doesn't exist and the cache is full, you can remove the least recently added memory type. Here's the updated function:

```cpp
void add(const MemoryType& mt) {
    bool exists = false;
    for (int i = 0; i < CACHEELEMS; ++i) {
        if (cache[i] == nullptr) {
            cache[i] = new MemoryType(mt);
            pos = (i + 1) % CACHEELEMS;
            return;
        } else if (*cache[i] == mt) {
            exists = true;
            break;
        }
    }
    if (!exists) {
        if (cache[pos] != nullptr) {
            delete cache[pos];
        }
        cache[pos] = new MemoryType(mt);
        pos = (pos + 1) % CACHEELEMS;
    }
}
```

2. For the `clear` function, you can use a boolean variable to check if the memory type has been found and removed. Here's the updated function:

```cpp
void clear(const MemoryType& mt) {
    bool found = false;
    for (int i = 0; i < CACHEELEMS; ++i) {
        if (cache[i] != nullptr && *cache[i] == mt) {
            if (!found) {
                delete cache[i];
                cache[i] = nullptr;
                found = true;
            }
        } else if (cache[i] == nullptr) {
            break;
        }
    }
}
```

3. For the `cacheManagement` function, you can add a function to count the occurrences of each memory type in the cache. Here's the updated function:

```cpp
void cacheManagement() {
    for (int i = 0; i < CACHEELEMS; ++i) {
        if (cache[i] != nullptr) {
            int count = 0;
            for (int j = 0; j < CACHEELEMS; ++j) {
                if (cache[j] != nullptr && *cache[j] == *cache[i]) {
                    count++;
                }
            }
            std::cout << "Memory type " << *cache[i] << " occurs " << count << " times in the cache." << std::endl;
        }
    }
    // rest of the code
}
```
assistant