Addresses

Postal addresses seem to be easy: – Name and/or Company – Street and/or PostBox – ZIP Code – Municipality – Country This is true in Germany or Switzerland and a few other countries. I would like to add, that in some large buildings it can be a good idea to add the apartment number, but …

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Phone Numbers and E-Mail Addresses

Most data that we deal with are strings or numbers or booleans and combinations of these into classes and collections. Dates can be expressed as string or number, but have enough specific logic to be seen as a fourth group of data. All these have interesting aspects, some of which have been discussed in this …

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Ranges of Dates and Times

In Software we often deal with ranges of dates and times. Let us look at it from the perspective of an end user. When we say something like „from 2020-03-07 to 2019-03-10“ we mean the set of all timestamps such that     or more accurately:     Important is, that we mean to include …

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How to get rid of these HTML-entities in Files

It has been written here that HTML-entities (these ä etc) should be avoided with the exception of those that we need due to the HTML-syntax like <, >, & and maybe " and  . They were already mostly obsolete more than 20 years ago, but in those days we still did not automatically use UTF-8 …

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UUIDs revisited

UUIDs have proven useful in many circumstances. We have basically two main variants: The UUID is calculated as a combination of the Ethernet-MAC-address, the timestamp and a counter. The UUID is calculated using a good random number generator While variant 1 provides for a good uniqueness, there are some issues with it. Today we use …

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Unicode and C

It is a common practice in C to use arrays of char as strings. The 0 is used as end marker. The whole thing was created like that in the 1970s and at that time it was kind of cool to get away with one less language feature and to express it in terms of …

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Tip: how to make Thunderbird use ISO Date Format

After an upgrade, my Thnderbird started to use a weird US-date format and forgot my setting for this. I did not find any setting either. But this seems to work fine: Create a shell script #!/bin/bash export LC_TIME=sv_SE.utf8 export LC_DATE=sv_SE.utf8 exec /usr/bin/thunderbird and make sure that this gets called when thunderbird is started instead of …

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Some thoughts about String equality

Of course Strings are today in some way Unicode. In this article we assume code points as the building blocks of Strings. That means for example in the Java-world, that we are talking about one code point being comprised of one Java character for typical European languages, using Latin, Greek or Cyrillic alphabets including extensions …

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The little obstacles of interoperability

Deutsch A lot of things in today’s IT landscape have been unified and interoperability is much better than 20 years ago. Some examples: Networking: Today networking is TCP/IP. Even the physical cables with RJ45/Ethernet and the wireless networks have been standardized and all kinds of devices can use the same networks. In the old days …

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Daylight Saving

In many countries of Europe we have to readjust our watches and clocks today, unless they do it automatically. It is interesting, that dealing with this has always been a great challenge for software engineers and a very high two digit percentage of software that in some way or other deals with time, does not …

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