棧接口的定義
- 定義棧的接口柄沮，具體的實(shí)現(xiàn)可以使用不同的底層數(shù)據(jù)結(jié)構(gòu)；
public interface Stack<E> {
int getSize();
boolean isEmpty();
void push(E e);
E pop();
E peek();
}
基于動(dòng)態(tài)數(shù)組實(shí)現(xiàn)的棧
- ArrayStack 底層使用了動(dòng)態(tài)數(shù)組實(shí)現(xiàn)了數(shù)據(jù)結(jié)構(gòu)棧庸论；
package _03.stack._02;
public class ArrayStack<E> implements Stack<E>{
private Array<E> array;
public ArrayStack(int capacity){
array = new Array<>(capacity);
}
public ArrayStack(){
array = new Array<>();
}
@Override
public int getSize(){
return array.getSize();
}
@Override
public boolean isEmpty(){
return array.isEmpty();
}
public int getCapacity(){
return array.getCapacity();
}
@Override
public void push(E e){
array.addLast(e);
}
@Override
public E pop(){
return array.removeLast();
}
@Override
public E peek(){
return array.getLast();
}
@Override
public String toString(){
StringBuilder res = new StringBuilder();
res.append("Stack: ");
res.append('[');
for(int i = 0 ; i < array.getSize() ; i ++){
res.append(array.get(i));
if(i != array.getSize() - 1)
res.append(", ");
}
res.append("] top");
return res.toString();
}
}
測試
public class Main {
public static void main(String[] args) {
ArrayStack<Integer> stack = new ArrayStack<>();
for(int i = 0 ; i < 5 ; i ++){
stack.push(i);
System.out.println(stack);
}
stack.pop();
System.out.println(stack);
}
}
輸出：
Stack: [0] top
Stack: [0, 1] top
Stack: [0, 1, 2] top
Stack: [0, 1, 2, 3] top
Stack: [0, 1, 2, 3, 4] top
Stack: [0, 1, 2, 3] top
