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SEARCH KEYWORD -- Subtract



  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

  Date interval add and sub prior to PHP 5.3

After PHP 5.3, we can use DateInterval object or date_interval_create_from_date_string() function to add or subtract days,weeks,months or years to or from a DateObject.But prior to PHP 5.3,we cannot do this. If we want to achieve the same effect. We need to use some skills. Here is one:We can use strtotime() function to achieve this. For example:$date=date('Y-m-d',time());$datestamp=strtotime(date('Y-m-d',strtotime($date)).' +1 day'); $datestamp=strtotime(date('Y-m-d',strtotime($date)).' +1...

   PHP,DateInterval,Class,PHP 5.3,PHP 5.2     2011-10-21 10:50:10

  Comparing Floating Point Numbers, 2012 Edition

We’ve finally reached the point in this series that I’ve been waiting for. In this post I am going to share the most crucial piece of floating-point math knowledge that I have. Here it is:[Floating-point] math is hard.You just won’t believe how vastly, hugely, mind-bogglingly hard it is. I mean, you may think it’s difficult to calculate when trains from Chicago and Los Angeles will collide, but that’s just peanuts to floating-point math.Seriously. Each ti...

   Floating point number,Comparison,True value     2012-02-23 07:11:03