import java.lang.*;
import java.util.*;
public class JavaLanguageDataStructure {
public static void main(String[] args) {
System.out.println("Hello World!");
System.out.println("This is the basic java data structure");
System.out.println("/****************************************/");
//basic data types
//primitive data types
byte myByte = 0101;
short myShort = 101;
int myNumInteger = 5;
long myLong = 100000000;
float myNumFloat = 5.99f;
double myNumDouble = 5.99;
char myChar = 'D';
boolean myBool = true;
System.out.println("myByte: " + myByte);
System.out.println("myShort: " + myShort);
System.out.println("myNumInteger: " + myNumInteger);
System.out.println("myLong: " + myLong);
System.out.println("myNumFloat: " + myNumFloat);
System.out.println("myNumDouble: " + myNumDouble);
System.out.println("myChar: " + myChar);
System.out.println("myBool: " + myBool);
//Non-Primitive datatype
System.out.println("/****************************************/");
System.out.println("/*************String*****************/");
String s = "Hello";
//Array
//Class
System.out.println("myString: " + s);
s.charAt(0);
s.length();
s.substring(0, 1);
s.substring(1);
s.subSequence(1, 3);
s.equals("abc");
s.equalsIgnoreCase("abc");
s = s.trim();
s.indexOf("e");
s.indexOf("e", 2);
s.lastIndexOf("e");
s.toCharArray();
Integer.valueOf("5"); //returns an Integer object
Integer.parseInt("5"); //returns an int primitive
String.valueOf(5); //integer to string
//String builder
StringBuilder sb = new StringBuilder();
sb.append("a");
sb.insert(0, "b");
sb.append("c");
sb.deleteCharAt(sb.length() - 1);
sb.reverse();
sb.toString();
//Array
int[] a = new int [10];
char[] b = {'a', 'b'};
int [][] c = new int[5][10];
int rows = c.length;
int cols = c[0].length;
int max = Integer.MAX_VALUE;
int min = Integer.MIN_VALUE;
Arrays.sort(a);
for(int i = 0; i < c.length; i++){
System.out.println(c[i]);
}
//List
List<Integer> list = new ArrayList<Integer>();
ArrayList<Integer> list1 = new ArrayList<Integer>();
List<List<Integer>> list2 = new ArrayList<List<Integer>>();
list.add(0);
list.add(0, 1);
list.add(3);
list.get(0);
list.size();
list.remove(list.size() - 1);
Collections.sort(list);
Collections.sort(list, Collections.reverseOrder());
Collections.sort(list, new Comparator<Integer>() {
@Override
public int compare(Integer o1, Integer o2) {
return o1 - o2;
}
});
//Stack
Stack<Integer> stack = new Stack<Integer>();
stack.push(0);
stack.push(1);
stack.peek();
stack.pop();
stack.isEmpty();
stack.size();
//Queue
Queue<Integer> q = new LinkedList<Integer>();
((LinkedList<Integer>) q).add(0);
q.add(1);
q.remove();
q.peek();
q.isEmpty();
q.size();
//HashMap
HashMap<Integer, String> map = new HashMap<Integer, String>();
map.put(1, "abc");
map.get(1);
map.put(2, "bcd");
if(map.containsKey(1))
{}
if(map.containsValue("abc")){
}
for(Integer k : map.keySet()){}
for(String v :map.values()){
}
map.isEmpty();
map.size();
//HashSet
HashSet<Integer> set = new HashSet<Integer>();
set.add(0);
set.add(1);
set.remove(0);
if(set.contains(0)){}
set.isEmpty();
set.size();
//min heap
PriorityQueue<Integer> pq = new PriorityQueue<Integer>();
pq.add(0);
pq.remove(0);
pq.add(1);
pq.peek();
pq.isEmpty();
pq.size();
while(!pq.isEmpty()){}
}
}
Java 基本数据类型和数据结构
最新推荐文章于 2024-03-12 14:27:41 发布