棧的特點:先進後出(LIFO),主要是對棧頂的操作。
作圖表示:
下面我們用棧實現字符串反轉例子:
1,首先實現我們自己的棧CharStack
public class CharStack {
private int maxSize;
private char[] arr;
private int top;
public CharStack(int maxSize) {
this.maxSize = maxSize;
this.arr = new char[maxSize];
top = -1;
}
/**
* 壓人數據
*
* @param data
*/
public void push(char data) {
arr[++top] = data;
}
/**
* 彈出數據
*/
public int pop() {
return arr[top--];
}
/**
* 訪問棧頂元素
*/
public int peek() {
return arr[top];
}
/**
* 棧是否爲空
*/
public boolean isEmpty() {
return top == -1;
}
/**
* 棧是否滿了
*/
public boolean isFull() {
return top == (maxSize -1);
}
}
2,定義實現字符串反轉的類
package com.tyj.stack;
public class Reverse {
private String str;
public Reverse(String str) {
this.str = str;
}
/**
* 思想:根據棧先進後出的特點,先遍歷所有字節push進去,再pop出來
*
* @return
*/
public String doReverse() {
int leagth = str.length();
CharStack charStack = new CharStack(leagth);
for (int i = 0; i < leagth; i++) {
charStack.push(this.str.charAt(i));
}
String s = "";
while (!charStack.isEmpty()) {
s += (char) charStack.pop() + "";
}
return s;
}
}
3,最後是我們的測試代碼。
public class TestReverse {
public static void main(String[] args) {
Reverse reverse = new Reverse("北京歡迎您!");
System.out.println(reverse.doReverse());
}
}
運行結果:!您迎歡京北