The ninth episode of the Aiti Tribe Clinic: Java, Python, PHP, they all say they are simple

【51CTO.com original article】 Activity description : Aiti Tribe is a service community that provides core developers with in-depth technical exchanges, solutions to development needs, and resource sharing. Based on this community, we invite industry technology experts to provide one-on-one breakthroughs on development needs and remove stumbling blocks in the development process. We help developers solve development problems with the most professional and efficient answers.

Topic keywords : Data type conversion overflow/pointer conversion/login/database/IoT/CDN

Tribe lineup : 51CTO community think tank

Object-oriented : Java development engineer, PHP development engineer, .NET engineer, C language development engineer

How to participate : Join the 51CTO developer QQ exchange group (627843829). If you have any technical questions, ask them in the group or send them to the group owner.

Event Details :

PHP-Wu-Beijing : I would like to ask the experts, how to convert int year=2017 in C to char *year_c ="2017"? Windows has a function to handle it. There is no direct function on Linux. char* is a pointer and uses double quotes.

1>Android-Xiaoyao-Chongqing : Just convert int to char? There are many ways, just search Baidu and you will know. There should be a corresponding library on Linux, just add the corresponding header file.

2>Java-with_prototype-Beijing : int is first converted into a character array, and the character array is converted into a pointer.

3> Programmer-shikoku-Hangzhou : There is no direct conversion function, you can only use the formatted form sprintf(str,"%d",aaa). Just this sentence, define the char array str, to ensure that its length can accommodate int.

Web Design-Xia Xian-Nanchang : Does anyone know what is going on?

Why is this equal to 0?

Shenzhen-Levi/Architecture : Data type conversion overflow, how big can a 32-bit unsigned number represent? Just do the math and you will know how big (2*2*2+2)^12 is. Decimal precision loss, single-precision decimals, 7 significant digits have been mentioned above, and the principles of computer organization have been discussed.

The results of floating point calculations are different.

ASP/SQL - Small Element - Yunnan : What's the problem?

Java+Li Sai+Zhengzhou : Try the end tag of <td>.

Java-Yuanjin-Guiyang : When logging in, it prompts that the username or password is wrong, but the login name and password are in the database. Why is this?

Java-with_prototype-Beijing : Check if userName/userPwd variables are empty.

ASP/SQL - Small Element - Yunnan : ASP connects to Server SQL to establish a hyperlink. It can jump but fails. The address becomes this. How can I make it jump directly to www.baidu.com?

Database Server SQL called by ASP.

<td width="80" align="center"><a href="<%=rs.fields(3).value%>"><%=rs.fields(3).value%></a> </td>

It is to get the fields from the database return. I use query, and the structure of the query table is:

Half-assed Full-Stack Craftsman - Cao Hongwei - Beijing : What is the database table structure for RS? RS stands for resultset, which is a record in the data set obtained after SQL query in the database.

<td width="80" align="center"><a href="http://<%=rs.fields(3).value%>"><%=rs.fields(1).value%></a> </td>

Try this.

<img src="<%=rs.fields(1).value%>" /> Use this code and it will work.

Java-Aiwanting-Beijing : Hello experts, I have a question about IoT technology? How can I collect data and transmit it to the console for display within one second? The current latency is 3-8 seconds. I have both Wifi and wired networks. Some are outdoors. I don't have data for each node, but the total time measured, calculated by a meter.

1>Python operation and maintenance development_howhy-Shenzhen : cache CDN, life cycle time.

2>BIGDATA_AI - Yida - Guangzhou : Data collection and transmission of the Internet of Things, the data collected is from sensors or RFID devices, transmitted through the network, and displayed on the console. The most time-consuming and unstable part is the network transmission. As for the display within 1 second, there is no problem in all aspects of the transmission, from the beginning of collection to the real-time transmission of data.

3> Half-baked full-stack craftsman - Cao Hongwei - Beijing : Starting from IOT, to your router, to your server, and then to the console front end, what is the delay of each segment? Is the entire path http or socket long connection? In the protocol, maintain a timestamp list and monitor it, otherwise God will not know where you are slow. Or summarize the logs of a request at each node and check it through the log. It is actually a full-link monitoring problem.

Network Engineer-sevenot-Chengdu : Is there any open source free MySQL remote management tool? Can you recommend one?

Java-Ha Han Langzi-Chengdu : Yes, navicat cracked version.

Cloud Computing - Cainiao - Suzhou : What do these mean?

Web-Poplar-Zhengzhou : Convert decimal to binary, add zeros in front. . . . You will know if you try it yourself. Don't worry about the words, convert to decimal, hexadecimal, binary, or octal. The specific definition is for those who study memory to understand. .

Java-Chen-Zhuhai : What is the output order? What values ​​are output by a and b respectively?

Android-Xiaoyao-Chongqing : 2 3 a=110, b0 1 4, Java basic questions.

Java-Wutongshu-Beijing : Who has Python videos that can share with me?

1>51CTO-Xiaoguan : Python Quick Start Video Course

2>Operation and maintenance - xwaqdyw - Tianjin : Link: https://pan.baidu.com/s/1bOiulC Password: nkmc This is already very complete for web development. Link: https://pan.baidu.com/s/1cIsU6M Password: adke There is also a set of automated operation and maintenance. I studied it by reading a book before. I haven't watched this video, but it is said to be quite complete. Comrades in operation and maintenance can study this set.

Xiaobai-Nothing-Zhongshan : Which programming language is more promising to learn now?

1>Department Management-Mingliang-Guangzhou : PHP is okay, but it is more difficult to find a job in .NET.

2> Backend - Liu Shengjie - Chengdu : I found that front-end is quite popular and many people are learning it.

Do you still have questions about these solutions? Welcome to join the 51CTO developer QQ exchange group 542270018 for discussion.

Next event notice: October 19

Keywords: Android development, Java, PHP, database, operation and maintenance

Activity Review:

The fourth episode of the Aiti tribe consultation: Application scenarios and functions of Java message queues

The fifth episode of the Aite tribe clinic: data collection and front-end application

The sixth episode of Aiti Tribe Clinic: How does machine learning judge emergencies?

The seventh episode of the Aite Tribe Clinic: What function was used to write the King of Pesticide Welfare Bureau?

The eighth episode of the Aiti Tribe Clinic: Eliminate these common Android development problems

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