59 lines
2.5 KiB
C++
59 lines
2.5 KiB
C++
#include "sequence.h"
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namespace seq
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{
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class DynamicArray: public Sequence
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{
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public:
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bool empty() const { return (this->logical_size == 0); } // test whether the array is empty
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size_t size() const { return this->logical_size; } // return the logical size (number of items in the array)
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// it is the caller's responsibility to ensure that the array is not empty!
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int& front() { return this->values[0]; } // return a reference to the first item
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int& back() { return this->values[this->logical_size - 1]; } // return a reference to the final item
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// return a reference to the item at position i of the sequence, counting from 0
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// we use modulo arithmetics to avoid over-/underflow; will still fail for an empty array
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int& at(int i) { return this->values[i % this->logical_size]; }
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/*
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* accepts an additional item into the dynamic array;
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* by default, this is done at the back end of the array
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* call push_front(...) to push an element at the front
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*
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* the array takes ownership of the copy (but not of the original!)
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*/
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void push(const int& pushed_item) { this->push_back(pushed_item); }
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void push_back(const int& pushed_item) { this->insert_at(this->logical_size, pushed_item); }
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void push_front(const int& pushed_item) { this->insert_at(0, pushed_item); }
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/*
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* removes an item from the list (back end by default)
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* to do the same at the front, call pop_front()
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*/
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void pop() { this->pop_back(); }
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void pop_front() { this->erase_at(0); }
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void pop_back() { this->erase_at(this->logical_size - 1); }
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void clear(); // remove all the items from the array
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void insert_at(int i, const int& inserted_item); // insert an item at index i
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void erase_at(int i); // remove the item at index i
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// overwrite the element at index i
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// we use modulo arithmetics to avoid over-/underflow; will still fail for an empty array
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void set_value_at(int i, const int& in_item) { this->values[i % this->logical_size] = in_item; }
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~DynamicArray() { this->clear(); }
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private:
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// this is a static C/C++ array containing the actual data
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// it is owned by the dynamic array
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int* values = nullptr;
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size_t logical_size = 0; // how many data items are we actually storing?
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size_t capacity = 0; // how much memory did we allocate?
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void resize(size_t new_capacity); // shift to static array with increased/decreased capacity
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};
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}
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