• Usage of lambda expression in C + +


    To explain, I use gcc7 1.0 compiler, standard library source code is also this version. This article explains the usage of lambda expressions in C + + 11. When I first came into contact with the keyword lambda, I remember it was still in Python, but in fact, we had this keyword in C + […]

  • Study day 8


    C language The general form of the for statement For — loop structure for( :) int a, sum = 0; for (a = 1; a <= 100; a++) { sum = sum + a; } printf(“sum=%d”, sum); A = 1 in parentheses is the initial value of the cyclic variable, a < = 100 is […]

  • Python technique: implement simple tokenizer with re module


    A simple tokenizer The tokenization task is the most common task in Python string processing. Here we will explain how to build a simple expression tokenizer with regular expressions, which can parse the expression string from left to right into a stream of tokens. Give the following expression string: text = ‘foo = 12 + […]

  • Do you really understand export default?


    export default Aandexport { A as default }At first glance, it looks the same, but there are some subtle differences. It is easier to leave a hole. This paper introduces the differences between the two writing methods. importStatement imports a reference, not a value If there is an export, there must be an import. Let’s […]

  • Python technique: implement simple recursive descent parser


    1. Arithmetic operation expression evaluation In the last blog postPython techniques: implementing simple tokenizer with re moduleIn, we introduce the use of regular expressions to match the corresponding patterns to realize a simple word segmentation. However, regular expression is not omnipotent. It is essentially a finite state machine (FSM), which cannot process text with recursive […]

  • Study day 10


    C language Array – batch defined variable – construction type One dimensional array Definition Name [constant expression]—— [] cannot contain variables int a[10]; Define that the size of the array is case dead quote Cannot reference the entire array int a,b[10]; for (a = 0; a <=9 ; a++) { a[b] = a; } for […]

  • Implementation of quartz timing task visual management with springboot


    preface In the actual framework or product development process, the integration of quarzt in springboot is basically directly hard coded in the form of bean objects of job and trigger. For example, the following code example. There is no dynamic global management for all scheduled task types, specific execution classes, execution strategies and running status […]

  • Inline, noinline and crossline of kotlin learning


    First, the conclusion, Inline: it is compiled by inline (that is, the function content is directly inserted into the calling function), which is used for the method Noinline: turn off this optimization locally to get rid of the restriction that function type parameters can not be used as objects. It is used for parameters Crossinline: […]

  • Kotlin of Android (I) — basic use of kotlin


    preface Kotlin is a static type programming language running on Java virtual machine. It is designed, developed and open source by JetBrains. Kotlin can be compiled into Java bytecode like a class file and run on a JVM. It can also be compiled into JavaScript to run on devices without a JVM. At the Google […]

  • Springboot + Kafka + elk complete massive log collection (super detailed)


    The overall process is as follows: Server preparation First list the server nodes here, so that students can check the corresponding contents by comparing the nodes below Springboot project preparation Log4j2 is introduced to replace the default log of springboot. The demo project structure is as follows: pom org.springframework.boot spring-boot-starter-web org.springframework.boot spring-boot-starter-logging org.springframework.boot spring-boot-starter-log4j2 com.lmax […]

  • C + + loop! Loop type + loop control statement + infinite loop!


    C + + loop Sometimes, you may need to execute the same piece of code multiple times. Generally, statements are executed sequentially: the first statement in a function is executed first, followed by the second statement, and so on. Programming languages provide a variety of control structures that allow more complex execution paths. Circular statements […]

  • Record an error caused by unspecified JDBC type


    Error reporting site restore A batch stored SQL is tested normally and reported online ### Error updating database. Cause: java. sql. Sqlsyntaxerrorexception: ora-01790: the expression must have the same data type as the corresponding expression The original SQL is written like this <insert id=”batchInsert”> insert into <include refid=”TABLE_NAME”/> ( CID, TS, PHONE, NUM_PACKAGE, COST_MONTHPRICE, COST_PRICE, […]