If you are a C or C++ programmer, you may familiar withe ungetc function in C. ungetc function is a very simple but useful function especially when your program need to read characters from a FILE stream for data parsing. You may encounter cases where you need to unread the character so that you can use that character when you pass in the FILE reference into another … [Read more...]
Archives for 2013
eGenting Programming Competition 2013
Another competition year has come! Get your programming skills polished and take the challenge! There are more prizes this year. Come eat for free (breakfast, lunch, tea break include) and registration is free. Remember to bring your weapons, books I meant :) … [Read more...]
SQL: How To Select Data With Same Values On Columns
Let say you have the following data in you database table t1 and you want to select the IDs for the row record that have the same value on COL1 and COL2. ID COL1 COL2 COL3 ====================== 1 100 200 300 2 200 300 400 3 100 200 500 4 300 300 300 5 200 300 400 And the expected result is ID = 1,2,3,5. The SQL to … [Read more...]
Linux: How To Add Swap on CentOS
Linux divides its physical memory (or the RAM, random access memory) into chucks of memory called pages. When a program require more memory and there isn't enough physical memory, Linux will starts moving out inactive pages and store them on hard disk. The process of moving out the pages for physical memory to disk is called swapping. The size of "memory on disk" is … [Read more...]
Virtualmin: How To Install Virtualmin in CentOS
I have recently moved all my websites to a SSD cloud hosting. I installed Virtualmin in the new server and found that it is very useful, powerful and the most important thing - it is free (open source software). … [Read more...]