ha, this is funny, almost 500 guys upvoted this, but no one explained the cryptic "invariant" for 10 years... finally jlau commented on it but I found more clear explanation: "An invariant is any logical rule that must be obeyed throughout the execution of your program that can be communicated to a human, but not to your compiler." thanks to: softwareengineering.stackexchange.com/a/364286 — starriet 30 secs ago

What you did wrong is what you're doing now. Your question is way too broad for this site. Please review Open letter to students with homework — Steve 18 secs ago

ha, this is funny, almost 500 guys upvoted this, but no one explained the cryptic "invariant" for 10 years... finally jlau commented on it, but this might be a more clear explanation to some of you: Invariant is a kind of "rule" that we developers should follow, but compilers have no idea about it. thanks to: softwareengineering.stackexchange.com/a/364286 — starriet 7 secs ago

I feel bad for non-English programmers that they need to learn how to spell "length" correctly. — Frank Yellin 10 secs ago

Unfortunately you asked on the wrong website. You should ask at softwarerecs.stackexchange.com — Amedee Van Gasse 1 min ago

I am sure you are starting to learn programming and Stackoverflow community can be ruthless. Python is usually used by developers and programmers while R is basically python for non-programmers. both are easy to learn and very similar especially in data manipluation etc. For example, Python as pandas for dataframes while in R dataframes are inbuilt. Python is used mostly by programmers while R is used by economists/ statisticians. It is not generic though. — Yasir Ahmed Pirkani 20 secs ago

Please take the tour to learn how Stack Overflow works and read How to Ask on how to improve the quality of your question. Then check the help center to see what questions you can ask. Please see: Why is “Is it possible to…” a poorly worded question?. — Progman 47 secs ago

See: softwareengineering.stackexchange.com/q/121555/281325 — rage 34 secs ago

No one can tell you why approval takes the time it takes. We are not Apple, so any answer would just be a guess. App store approval questions are off topic for Stack Overflow in any case. Apple is a big unpredictable corporation. And we are programmers, not mind-readers. — matt 46 secs ago

@Brunol55: it is required (softwareengineering.stackexchange.com/a/188861/166310). It would also be unsafe since an internet crawler makes GET requests and could thus "by accident" edit/remove/... an entry. Furthermore for a GET request, no CSRF validation is performed. — Willem Van Onsem 31 secs ago

Re “I guess”: This is not a useful technique for software engineering. — Eric Postpischil 35 secs ago

Also note printf() returns the number of characters output, scanf() returns the number of successful conversions. (it will save you 10-fold if you just spend an hour and read man 3 scanf and understand in depth how the format-string, the optional-modifiers and each conversion specifier behaves. scanf() is probably the No. 1 misused function by new C programmers (and probably responsible for 1:5 questions here) Understanding it fully is time well spent. Then you will know why user-input should be done with fgets() :) — David C. Rankin 6 secs ago