package basic;

import java.nio.charset.StandardCharsets;

/**

* TODO: Chinese String

*/

import java.util.Arrays;

import java.util.Scanner;

public class Main01 {

public static void main(String[] args) {

System.out.println("\nmian fang fa...hello world!");

for (String x : args) {

System.out.println(x);

if ("-version".equals(x)) {

System.out.println("no version yet");

}

}

Main01.java_operator();

Main01.java_type();

Main01.java_trans_type();

Main01.java_boolean_op();

Main01.java_string();

Main01.java_array();

// Main01.java_io();

Main01.java_flow_control();

Main01.java_format();

Main01.java_subclass();

}

private static void java_operator() {

System.out.println("\nJava_operator");

System.out.println(100 / 9);

System.out.println(100.0 / 9);

System.out.println(100 / 9.0);

System.out.println(3 % 2);

System.out.println(4 % 2);

System.out.println(3.0 % 2);

}

private static void java_type() {

System.out.println("\nJava_type");

byte b = 127; // -128 ~ 127

short s = 32767; // -32768 ~ 32767

int i = 2147483647; // -2147483648 ~ 2147483647

long l = -9_223_372_036_854_775_808L; // -9,223,372,036,854,775,808 ~ 9,223,372,036,854,775,807

System.out.println(b);

System.out.println(s);

System.out.println(i);

System.out.println(l);

System.out.println(0xff0000);// 16711680

System.out.println(0b1000000000);// 512

System.out.println(Integer.toHexString(233)); // e9

System.out.println(Integer.toBinaryString(233)); // 11101001

final int MY_233 = 233;

System.out.println(MY_233);

}

private static void java_trans_type() {

System.out.println("\njava_trans_type");

System.out.println((int) (3.2 + 0.5));

System.out.println((int) 1e20);

}

private static void java_boolean_op() {

System.out.println("\njava_boolean_op");

System.out.println(true);

System.out.println(false);

System.out.println(!true);

System.out.println(false && (1 / 0 > 0));

System.out.println(true || (1 / 0 > 0));

System.out.println(true ? -233 : 233);

}

private static void java_string() {

System.out.println("\njava_string");

System.out.println('A');

System.out.println((int) ('A'));

// System.out.println("*"); //TODO chinese support

System.out.println('\u0041');

System.out.println('\u4e2d');

// System.out.println((int) ('*')); //TODO chinese support

String a = null;

System.out.println(a);

System.out.println("");

System.out.println("hello " + "world");

String s1 = "hello", s2 = "Hello".toLowerCase();

String s3 = s1;

System.out.printf("s1==s2: %s; s1.equals(s2): %s \n", String.valueOf(s1 == s2), String.valueOf(s1.equals(s2)));

System.out.printf("s1==s3: %s; s1.equals(s3): %s \n", String.valueOf(s1 == s3), String.valueOf(s1.equals(s3)));

System.out.println(s1.contains("ll"));

System.out.println(s1.indexOf("ll"));

System.out.println(s1.indexOf("l"));

System.out.println(s1.lastIndexOf("l"));

System.out.println(s1.startsWith("he"));

System.out.println(s1.endsWith("he"));

System.out.println(" \t\r\nhello\n\r\t".trim());

System.out.println("hello world".substring(2, 4));

System.out.println("hElLo WoRlD".toUpperCase().toLowerCase());

System.out.println("hello world".replace('l', 'L'));

System.out.println("hello world".replace("ll", "LL"));

System.out.println(String.join("~", "A,,B;C ,D".split("[,; ]+")));

System.out.println("valueOf(int): " + String.valueOf(233));

System.out.println("valueOf(boolean): " + String.valueOf(true));

System.out.println("valueOf(object): " + String.valueOf(new Object()));

System.out.println("parseInt(int): " + String.valueOf(Integer.parseInt("233") - 1));

System.out.println("valueOf(String): " + String.valueOf(Integer.valueOf("233") + 1));

Integer n1 = new Integer(233);

Integer n2 = Integer.valueOf(233);

Integer n3 = Integer.valueOf("233");

Integer n4 = 233;

String s5 = n1.toString();

int x1 = n1.intValue();

int x2 = Integer.parseInt("233");

int x3 = n1;

Number n5 = Integer.valueOf(233) + 1;

System.out.println(n5.floatValue());

System.out.println("hello".toCharArray());

char[] cs1 = { '2', '3', '3' };

System.out.println(new String(cs1));

final byte[] bs1 = "hello".getBytes(StandardCharsets.UTF_8); // strange, Fail when use "UTF-8"

System.out.println(new String(bs1, StandardCharsets.UTF_8));

// System.out.println(new String("hello".getBytes("UTF-8"), "UTF-8"));

// System.out.println(new String("hello".getBytes("UTF-8"),

// StandardCharsets.UTF_8));

StringBuilder sb1 = new StringBuilder(128);

for (int i = 0; i < 100; i++) {

sb1.append(String.valueOf(i));

}

System.out.println(sb1.toString());

StringBuilder sb2 = new StringBuilder(128);

System.out.println(sb2.append("Mr ").append("233").append("!").insert(0, "Hello, ").toString());

}

private static void java_array() {

System.out.println(("\njava_array"));

int[] z0 = new int[5];

int[] z1 = { 2, 0, 3, 0, 0 };

int[] z2 = z1; // z1, z2 share memory

z2[4] = 3;

System.out.println(z2[0]);

System.out.println(z2[1]);

System.out.println(z2[2]);

System.out.println(z2[3]);

System.out.println(z2[4]);

System.out.println(z2.length);

System.out.println(Arrays.toString(z1));

System.out.println(Arrays.toString(z2));

Arrays.sort(z2);

System.out.println(Arrays.toString(z1));

System.out.println(Arrays.toString(z2));

int[][] z3 = { { 1 }, { 2, 3 }, { 4, 5, 6 } };

System.out.println(Arrays.deepToString(z3));

for (int[] i : z3) {

System.out.println(Arrays.toString(i));

}

}

private static void java_io() {

System.out.println("\njava_io");

Scanner z1 = new Scanner(System.in);

System.out.print("please input sth: ");

String z2 = z1.nextLine();

System.out.print("233: ");

System.out.println(z2);

System.out.print("please input double: ");

double z3 = z1.nextDouble();

System.out.printf("233: %7.2f\n", z3);

System.out.printf("%2$s %1$s\n", "world", "hello");

z1.close();

}

private static void java_flow_control() {

System.out.println("\njava_flow_control");

double x = 233.1;

if (Math.abs(x - 233) <= 1e-3) {

System.out.println("abs(x-233) <= 1e-3");

} else if (x > 233 + 1e-3) {

System.out.println("x > 233+1e-3");

} else {

System.out.println("x < 233-1e-3");

}

int x1 = 1;

switch (x1) {

case 0:

System.out.println("x1==0");

case 1:

case 2:

System.out.println("x1==1");

default:

System.out.println("default");

}

int x2 = 3;

while (x2 < 5) {

System.out.printf("x2 = %d\n", x2);

x2++;

}

do {

System.out.printf("x2 = %d\n", x2);

x2--;

} while (x2 > 2);

int[] x3 = { 1, 4, 9 };

for (int i = 0; i < x3.length; i++) {

System.out.printf("i = %d\n", i);

}

for (int x4 : x3) {

System.out.printf("x = %d\n", x4);

}

}

private static void java_format() {

System.out.println("\njava_format");

System.out.printf("%s is %d years old\n", "Bob", 233);

System.out.printf("%d; %x\n", 233, 233, 2.33); // 233; e9

System.out.printf("%f; %7.2f; %e; %+.2f\n", 233.0, 233.0, 233.0, 233.0);

System.out.printf("%2$d %3$d %1$d\n", 3, 2, 3);

}

private static void java_subclass() {

System.out.println("\nJava subclass");

Main01 m = new Main01();

Main01.SubClass x = m.new SubClass();

x.fn1();

}

public class SubClass {

void fn1() {

System.out.println("233: ");

}

}

}