{"id":53593,"date":"2021-10-12T03:01:26","date_gmt":"2021-10-11T17:01:26","guid":{"rendered":"http:\/\/www.rjmprogramming.com.au\/ITblog\/?p=53593"},"modified":"2021-10-10T18:24:13","modified_gmt":"2021-10-10T08:24:13","slug":"javascript-incrementing-and-decrementing-primer-tutorial","status":"publish","type":"post","link":"https:\/\/www.rjmprogramming.com.au\/ITblog\/javascript-incrementing-and-decrementing-primer-tutorial\/","title":{"rendered":"Javascript Incrementing and Decrementing Primer Tutorial"},"content":{"rendered":"
\"Javascript<\/a>

Javascript Incrementing and Decrementing Primer Tutorial<\/p><\/div>\n

Sometimes writing Javascript code we’ve let code like …<\/p>\n


\n<script type='text\/javascript'>
\n var counter=null;
\n

\n function initializeCounter() {
\n counter=0;
\n }
\n

\n function incrementCounter() {
\n if (counter == null) {<\/b>
\n counter=0;<\/b>
\n }<\/b>
\n ++counter;
\n }
\n

\n if (eval(Math.floor(Math.random() * 1746765765) % 2) == 1) {
\n initializeCounter();
\n } else {
\n incrementCounter(); \/\/ if called first, is interesting
\n }
\n<\/script>
\n<\/code><\/p>\n

… go through to the keeper. There’s nothing intrinsically<\/i> wrong with it. But the other day, thanks to Device Orientation \u2018alpha\u2019
\nCalibration … World-based calibration on iOS<\/a>, we learnt that the “if”<\/b> bracketing above can be superfluous in the sense that that same code above could be written …<\/p>\n


\n<script type='text\/javascript'>
\n var counter=null;
\n

\n function initializeCounter() {
\n counter=0;
\n }
\n

\n function incrementCounter() {
\n ++(+counter); \/\/ ... more succinctly
\n }
\n

\n if (eval(Math.floor(Math.random() * 1746765765) % 2) == 1) {
\n initializeCounter();
\n } else {
\n incrementCounter(); \/\/ if called first, is interesting
\n }
\n<\/script>
\n<\/code><\/p>\n

And so, we thought we’d write today’s proof of concept plus_avoids_zero.html<\/a>‘s live run<\/a> link in order for a user to try out some “Prefix style” incrementing and decrementing of Javascript variables<\/font> …<\/p>\n