0319ArraySelf.cpp

/* deleteItem() , peek() 구현 */
#include <iostream>
using namespace std;
class ArrayList {
	int capacity;
	int size;
	int *arrayLink;
public:
	ArrayList() {
		this->size=0;
		this->capacity=4;
		arrayLink = new int[capacity];
	}
	int getSize() { return size; }
	int isEmpty() { return size == 0; }
	int getCapacity() { return capacity; }
	void insertItem(int newItem, int k);
	int deleteItem(int k); //인덱스 k인 곳 삭제
	void insertLast(int newItem);
	int peek(int k);//인덱스 k인 배열 읽기
	void reSize(int newSize);
	void print();
};
int ArrayList::peek(int k) {
	int temp;
	temp = arrayLink[k];
	return temp;
}
void ArrayList::reSize(int newSize) {
	int *temp = new int[newSize];
	for(int i=0; i<size; i++) temp[i]=arrayLink[i];
	arrayLink = temp; 
}
void ArrayList::insertLast(int newItem) {
	if(size==capacity) {
		capacity *= 2;	
		reSize(capacity);
	}
	arrayLink[size++] = newItem;
} 
void ArrayList::print() {
	if(isEmpty())
		cout<<"배열이 비어있음";
	else
		for(int i=0; i<size; i++) cout<<arrayLink[i]<<"\t";
	cout<<endl;
}
void ArrayList::insertItem(int newItem, int k) {
	if(k>size) {
		cout<<"배열의 크기에 벗어난 인덱스 입니다."<<endl;
		return;
	}
	if(size==capacity) {
		capacity *= 2;
		reSize(capacity);
	}
	for(int i=size-1; i>=k; i--)
		arrayLink[i+1] = arrayLink[i];
	arrayLink[k] = newItem;
	size++;
}
int ArrayList::deleteItem(int k) {
	for(int i=k; i<size-1; i++) 
		arrayLink[i] = arrayLink[i+1];
	size--;
	if(size<capacity*0.5) {
		capacity -=4;
		reSize(capacity);
	}
}
int main() {
	ArrayList arr;	
	arr.insertLast(10);	arr.insertItem(20, 1);	arr.insertItem(30,2);
	arr.insertLast(40);	arr.insertLast(50);	arr.insertLast(60);
	arr.print();
	arr.insertItem(100, 4); arr.print();
	cout<<"크기: "<<arr.getSize()<<"용량: "<<arr.getCapacity()<<endl;
	cout<<"선택한 값: "<<arr.peek(5)<<endl;
	cout<<endl;
	arr.deleteItem(5);	arr.print();
	arr.deleteItem(2);	arr.print(); 
	arr.deleteItem(1); 	arr.print();	arr.deleteItem(0);	arr.print();
	arr.deleteItem(0);	arr.print();
	cout<<"크기: "<<arr.getSize()<<"용량: "<<arr.getCapacity()<<endl;
}