operatorstack.java

大整数计算器

package 大整数计算器;

public class OperatorStack {
    protected Operator elementData[];// 向量内容数组

    protected int elementCount;

    public OperatorStack() {
        elementData = new Operator[10];
        elementCount = 0;
    }

    public OperatorStack(int i) {
        elementData = new Operator[i];
        elementCount = 0;
    }
    
    public int length(){
        return elementCount;
    }
    
    public Operator get(int index) {
        if(index>=elementCount) return null;
        return elementData[index];
    }
    
    public Operator top(){
        return elementData[elementCount-1];
    }

    public Operator set(int index, Operator op) {
        Operator previous = elementData[index];
        elementData[index] = op;
        return previous;
    }

    public void push(Operator obj) {
        if (elementCount == elementData.length) {
            Operator newElementData[] = new Operator[elementCount + 1];
            for (int i = 0; i < elementCount; i++)
                newElementData[i] = elementData[i];
            elementData = newElementData;
        }
        elementData[elementCount] = obj;
        elementCount++;
    }
    public Operator pop(){
        elementCount--;
        return elementData[elementCount];
    }
}