myvector.java

来自「能完成矩阵的基本操作(加,减,乘,除,转置,求逆等)」· Java 代码 · 共 56 行

public class MyVector{
	private Object[] elementData;
	private int elementCount;
	
	public MyVector(){
		this(10);
	}
	private void ensureCapacity(int minCapacity){
		int oldCapacity = elementData.length;
		if (minCapacity > oldCapacity) {
	   		Object oldData[] = elementData;
	    	int newCapacity = oldCapacity * 2;
    	    if (newCapacity < minCapacity) {
					newCapacity = minCapacity;
	    	}
	    	elementData = new Object[newCapacity];
	    	System.arraycopy(oldData, 0, elementData, 0, elementCount);
		}	
	}
	public MyVector(int initialCapacity){
		elementData = new Object[initialCapacity];
		elementCount = 0;
	}
	
	public void add(int index,Object element){
		if (index >= elementCount + 1) {
	    	throw new ArrayIndexOutOfBoundsException(index + " > " + elementCount);
		}
		ensureCapacity(elementCount + 1);
		System.arraycopy(elementData, index, elementData, index + 1, elementCount - index);
		elementData[index] = element;
		elementCount++;
	}
	
	public void add(Object element){
		add(elementCount,element);
	}
	
	public void set(int index,Object element){
		if (index >= elementCount) {
	    	throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount);
		}
		elementData[index] = element;
	}
	
	public Object get(int index){
		if (index >= elementCount)
	    	throw new ArrayIndexOutOfBoundsException(index);
		return elementData[index];
	}
	
	public int size(){
		return elementCount;
	}
}