gooooloo

Understanding network programming as mail system

用写信的方式理解网络编程

2014/3/14

I have NO experience on network programming at all. Recently I learnt something, they are interesting. I am trying to summarize what I have learned as my own understanding way -- the mail system. Special thanks to Barteur Zhou.

我以前从没有过网络编程的经验和知识。最近学了一些，还挺好玩的。在这里，我想试试用自己的理解方式来总结下我近来所学的知识 -- 用写信的方式来类比。特别感谢 Barteur Zhou。

ip & port for net

gooooloo

package com.qidu.lin;

public class PrinterNumbers
{
	/**
	 * 打印螺旋矩阵
0  31  30  29  28  27  26  25  24 
1  32  55  54  53  52  51  50  23 
2  33  56  71  70  69  68  49  22 
3  34  57  72  79  78  67  48  21 

gooooloo

HTTPS in laymen's terms

###HTTP的问题：

• 传输过程没加密
• 不能确保对方是正牌的服务器
• 不能确保传输过程中没有被调包

举个例子讲就是，你要让快递把一个包裹寄给你朋友。有如下问题：

gooooloo

package info.gooooloo;

public class MyLineInfo {
    public static String info() {
        final StackTraceElement element = new Exception().getStackTrace()[1];
        return String.format("%s#%s,%s:%d",
                element.getClassName(),
                element.getMethodName(),
                element.getFileName(),
                element.getLineNumber());

gooooloo

public class Untitled {
     public static void main(String[] args) {

         final int N = 9;
         int[][] a = new int[N][N];

         int x = -1; int y = 0;
         int dx = 0; int dy = -1;

         int k = 1;

gooooloo

/**
 * Codes to implement the approximation of compute(x) of paper https://arxiv.org/pdf/1702.07825.pdf
 */
import java.util.Random;

public class Test {

    static float eTilde(float x) {
        final float x2 = x * x;
        final float x4 = x2 * x2;

gooooloo

# 模拟这个题目的过程
# https://mp.weixin.qq.com/s?__biz=MzIzMTc0NzAwMA==&mid=2247483759&idx=1&sn=933d3522dcc197b547696ad522652b8b&key=281224a0b07438ec8edb2e3a289a23f072754ac6a4b26d9e3ce3e38cca13ec9be38b36c21c8340b80c94deb264a2ff916029a398d55725d4128d04bbbef6653083d77490729372eca7851e6b4673eac2&ascene=0&uin=MTQ0OTk4MDMwMA%3D%3D&devicetype=iMac+MacBookPro11%2C1+OSX+OSX+10.12.4+build(16E195)&version=12020510&nettype=WIFI&fontScale=100&pass_ticket=1TrgoYI6A%2Fe9EM1BEXmWAwjoNDPwfCcCsU5W1LgXMf%2BV1wgkhzYikLhX8b3Ru9op

import numpy as np
import matplotlib.pyplot as plt

def f0(xarr, a, c, d):
    l = []
    cyclelen = d + 1.0 * c / a
    for x in xarr:

gooooloo

def main(a):
    a = abs(a)
    b = a
    c = 0
    while b > 0:
        c = c * 10 + b % 10
        b //= 10
    print(c == a)

if __name__ == '__main__':

gooooloo

class Node:
    def __init__(self, v, n=None):
        self.v = v
        self.n = n

def do_print(head: Node):
    t = head
    print('=====')
    while t is not None:
        print(t.v)

gooooloo

def main(n):
    delta = [(1,0), (0,1), (-1,0), (0,-1)]
    arr = [[0 for _ in range(n)] for _ in range(n)]
    row,col,k,di = -1,0,1,0
    while k <= n*n:
        row += delta[di][0]
        col += delta[di][1]
        if not 0 <= row < n or not 0 <= col < n or arr[row][col] > 0:
            row -= delta[di][0]
            col -= delta[di][1]