|
Training, Open Source Programming Languages This is page http://www.wellho.net/mouth/1669_Wha ... ming-.html Our email: info@wellho.net • Phone: 01144 1225 708225 |
| For 2023 (and 2024 ...) - we are now fully retired from IT training. We have made many, many friends over 25 years of teaching about Python, Tcl, Perl, PHP, Lua, Java, C and C++ - and MySQL, Linux and Solaris/SunOS too. Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own risk. Lisa and I (Graham) now live in what was our training centre in Melksham - happy to meet with former delegates here - but do check ahead before coming round. We are far from inactive - rather, enjoying the times that we are retired but still healthy enough in mind and body to be active! I am also active in many other area and still look after a lot of web sites - you can find an index ((here)) |
|
What are Unions (C programming)
Structures are used to hold a whole lot of different pieces of data in a collection - by element name not number. Sometimes, you [82][ac] Ä ll only want to hold some elements of your structure in specific circumstances - a good example is where you have a whole lot of similar things you [82][ac] Ä re describing, but only a limited range of elements applied to each. A very good example in real [82][ac] Ä system [82][ac] Ä programming is an X Windows event - each has a time stamp and a sequence number, and an event type, and each has a target window. But only some of them have X and Y co-ordinates, only some of them have keypresses and statuses, and so on. One possible way of holding such events would be a sparsely populated structure, but in practise this would be very wasteful of memory - so a union is used. (written 2008-06-08, updated 2008-06-10) Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles C209 - C and C based languages - Structures and Unions[1478] Some new C programming examples - files, structs, unions etc - (2007-12-19) [1572] C - structs and unions, C++ classes and polymorphism - (2008-03-13) [1584] Using Structs and Unions together effectively in C - (2008-03-21) [2573] C Structs - what, how and why - (2010-01-13) [3122] When is a program complete? - (2011-01-06) [3145] Structures v Structure Pointers in C. How, which, why. - (2011-01-25) [3386] Adding the pieces together to make a complete language - C - (2011-08-11)
Some other Articles
Spam Filters ... are working!The Composting Cone Challenge Compiling C programs with gcc - an overview Dynamic Memory Allocation in C What are Unions (C programming) Talk on TransWilts train service to Green Party Checking server performance for PHP generated pages Slow boot and terminal start on Linux boxes Factory method example - Perl Example of OO in Perl |
4759 posts, page by page
Link to page ... 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96 at 50 posts per pageThis is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.
Link to Ezine home page (for reading).
Link to Blogging home page (to add comments).
PH: 01144 1225 708225 • EMAIL: info@wellho.net • WEB: http://www.wellho.net • SKYPE: wellho
PAGE: http://www.wellho.net/mouth/1669_Wha ... ming-.html • PAGE BUILT: Sun Oct 11 16:07:41 2020 • BUILD SYSTEM: JelliaJamb