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i actually just started learning C++ and i was used to writing (var==0) like this in C but my C++ sir told me 0==var is more better way when i asked him why he told me you find out yourself so igoogled this thing but didnt find any info regarding this so im here to ask it anyone can help?

Govardhan Shah
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  • depends what is `var` i think – Alberto Sinigaglia Jul 31 '20 at 12:07
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    Some people refer to this as a ["yoda condition"](https://en.wikipedia.org/wiki/Yoda_conditions), which is why it might feel unnatural. It's to discourage accidentally writing an assignment expression instead. A proper linter should warn you anyway if you accidentally put an assignment in a conditional expression, so really this is more up to personal preference than it is a best practice. – Patrick Roberts Jul 31 '20 at 12:09
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    Adequate compilers, with adequate options, make it absolutely 100% equivalent. `if (0 == var)` looks awkward IMHO – pmg Jul 31 '20 at 12:16
  • @PatrickRoberts *A proper linter should warn you anyway if you accidentally put an assignment in a conditional expression* And that's why putting any assignments at all into a conditional expression is always **BAD**. Because when you do it accidentally, the one warning among several hundred or more deliberate uses will be missed and you will have created an almost-impossible-to-find bug. Writing bug-free code is hard enough. I have no idea why way too many C programmers insist on using a style that makes creating hard-to-find bugs easier to do. "Brevity of code" is cargo-cult BS here – Andrew Henle Jul 31 '20 at 12:18
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    For better readability you should use the following: ***Left-hand side:** The expression “being interrogated,” whose value is more in flux. **Right-hand side:** The expression being compared against, whose value is more constant. This guideline matches English usage—it’s pretty natural to say, “if you make at least $100K/year” or “if you are at least 18 years old.” It’s unnatural to say, “if 18 years is less than or equal to your age.”* - [The Art of Readable Code (Theory in Practice)](https://isbnsearch.org/isbn/9780596802295) – 3limin4t0r Jul 31 '20 at 12:23
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    @AndrewHenle At least with gcc, the warning can be silenced by using an extra set of parenthesis, i.e. `if ((var = 0))`, so that way you're not left with any warnings you "know" are fine that you have to filter out. – dbush Jul 31 '20 at 12:26
  • @AndrewHenle depending on situation it may well be utterly essential to put the comparison in the expression. Memory limited applications for example where creating a temporary boolean to contain the result of the comparison is impossible. And of course there's always the idea that being more concise is a great way to reduce potential bugs, and that includes cutting out such temporary placeholder variables in many situations. – jwenting Jul 31 '20 at 12:42
  • @jwenting *being more concise is a great way to reduce potential bugs* Human minds can accurately keep track of only 3-5 things at once, so cramming too much into a single line of code is **not** going to reduce bugs. Doing an assignment in a conditional expression uses up one of those precious items in the human mind. Most of the time completely needlessly. *cutting out such temporary placeholder variables* That's a totally nonsensical statement in the context of doing assignments in a conditional expression. You can't do an assignment **without** a variable. – Andrew Henle Jul 31 '20 at 14:47
  • @jwenting At least you're thinking about code styles with the purpose of reducing bugs in mind. I wonder how many readers of this have never even thought about how their personally-preferred style either contributes to or reduces the creation of bugs. – Andrew Henle Jul 31 '20 at 14:51
  • I wouldn’t prefer either. I'd use `!var` – M. Nejat Aydin Jul 31 '20 at 19:12

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