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SEARCH KEYWORD -- Bitwise operator

  Why you should be careful about optimizations

In one of my current javascript projects, I have to deal with 3D voxel coordinates. And, sometimes, I have floating points coordinates which must be converted to integers in order to convert them into proper array index. Javascript is a wonderful language, really. However, implementations are sometimes weird, and the way to do something can sometimes have very huge impacts on the performances. Worse, sometimes the classical way is more expensive than the tricky one. So, some peo...

   JavaScript,Bitwise,Floor,Trick,Optimization     2012-05-02 11:29:20

  Implementation of +,-,*,/ with bitwise operator

There is a question asked on Stackoverflow : Divide a number by 3 without using *,/,+,-,% operators. This question is an Oracle interview question. Some people give excellent answers. You can go there and take a look. Usually we need to use bitwise operators to do this kind of implementations. Here I want to show you ways to implement +,-,*,/ with bitwise operators. A bitwise operation operates on one or more bit patterns or binary numerals at the level of their individual bits. It is a fast, pr...

   Bitwise operator,Shift,Add,Subtract,Multiplication,Division     2012-08-05 01:52:47

  Hexadecimal and long in Java

Today I encountered a hexadecimal operation problem when I was implementing a bit reverse function for integer type. Basically in the implementation, there is an operation which is to do the bit operation & between one long integer and a hexadecimal number 0x00000000FFFFFFFFF. I was expecting that the high 32 bits of the long integer will be zeroed. But unfortunately I didn't get the expected result. The basic implementation is: long num=0x00F0_0000; num = (num>>16) | (num<<16); ...

   Hexadecimal,long,Java,bitwise operation     2014-06-18 23:44:32

  <=> operator in MySQL

Have you ever seen "<=>" in a SQL query while using MySQL? Does it mean less and equals to and greater than? Actually if you consider it as the union of <= and =>, great, you are close to it. This is one form of equal operator in MySQL, it has the similar meaning to the = operator with some subtle difference. According to MySQL documentation, <=> is NULL-safe equal. This operator performs an equality comparison like the = operator, but returns 1 rather than NULL if both operand...

   MySQL,NULL safe,<=>     2014-03-24 06:23:22

  JavaScript's New Features: Exploring the Latest Additions to the Language

As the web continues to evolve, so too does the JavaScript ecosystem. With the release of ECMAScript 2023 (ES2023), JavaScript developers can now leverage a range of new features that promise to improve code quality, readability, and maintainability. In this blog post, we'll dive into some of ES2023's most exciting additions and provide practical examples of how they can be used in your projects. 1. Private Fields and Methods in Classes One of the most anticipated features in ES2023 is the intro...

   JAVASCRIPT,ES2023     2023-04-16 01:41:58

  new expression vs operator new in C++

In C++, there is a new mechanism for memory allocation and management. When we want to initialize an object, we can use new expression to get enough memory for storing an object and also initialize the object. When we want to create a new object, we can use new expression, for example: Obj *obj=new Obj; Basically, what the new expression does is to allocate enough memory for storing the obj object, in addition, it will initialize the object with some intial values. Also, there is an operator new...

   C++, new expression, operator new     2012-08-12 11:42:39

  How to hide PHP Notice & Warning Messages

How to hide PHP Notice & Warning Messages. The PHP notice errors are frustrating and you are tired of seeing them when you are working on your scripts. They are showed at the beggining of your pages and may reveal confidential information to the visitor like the path to the file or the php file name in some cases.// Turn off all error reportingerror_reporting(0);// Report simple running errorserror_reporting(E_ERROR | E_WARNING | E_PARSE);// Reporting E_NOTICE can be good too (to report unin...

   PHP,Error,Warning,Deprecated,Hiding,Method     2011-11-18 12:17:26

  malloc/free and new/delete in C++

malloc and free are C++/C language standard library functions, while new/delete are operator of C++. They can be used to allocate dynamic memory and free memory in C++ programs malloc/free can not meet the requirements of dynamic objects creation. Object needs to call the constructor to initialize the object when creating, the object needs to call the destructor before it is destroyed  Since malloc() and free() are library functions rather than operators, the compiler has no control permiss...

   C++,memory,malloc,free,new,delete     2012-06-20 06:52:09

  Accurate floating point number calculation in JavaScript

In JavaScript, since floating point is defined with IEEE754,there will be some accuracy issues while doing floating point number arithmetic. Here is a function which can resolve the accuracy issue. var calc = function(num1,operator,num2,len){    var numFixs = function(num){        var arr = num.toFixed(len).toString().split('.');        return parseInt(arr.join(''));    }    switch(operator){...

   JavaScript, floating point,IEEE 754,accuracy     2012-12-27 11:07:49

  Only 4G can resolve the conflicts between China Telecom Carriers and WeChat ?

Why WeChat has made the three big Chinese telecom companies uncomfortable? Let's analyze from both technical and commercial levels. From a technical point of view, Mr. Huang, Dean of China Mobile Research Institute, described the impact of "always online service" applications like WeChat. Instead of using technical terms, we will explain in simple vivid phrases. First, mobile QQ, or WeChat, will have their own "request frequency". These requests are sent to the carrier network, to check the re...

   4G,WeChat,Telecom,China     2013-03-25 08:28:59

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