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How to repeat a string a variable number of times in C++?

...ster implementation, the idea is to minimise copying operations and memory allocations by first exponentially growing the string: #include <string> #include <cstddef> std::string repeat(std::string str, const std::size_t n) { if (n == 0) { str.clear(); str.shrink_to...
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How do you create optional arguments in php?

...ny attributes need to be processed, you can use the variadic argument list token(...) introduced in PHP 5.6 (see full documentation here). Syntax: function <functionName> ([<type> ]...<$paramName>) {} For example: function someVariadricFunc(...$arguments) { foreach ($argumen...
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Is there a regular expression to detect a valid regular expression?

...re pretty self-explanatory. SKIP : { " " | "\r" | "\t" | "\n" } TOKEN : { < DIGITO: ["0" - "9"] > | < MAYUSCULA: ["A" - "Z"] > | < MINUSCULA: ["a" - "z"] > | < LAMBDA: "LAMBDA" > | < VACIO: "VACIO" > } IRegularExpression Expression() : { IRe...
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Rule-of-Three becomes Rule-of-Five with C++11?

...p;& other) as Philipp points out in his answer, if it has dynamically allocated members, or generally stores pointers. Just like you should have a copy-ctor, assignment operator and destructor if the points mentioned before apply. Thoughts? ...
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Ruby: How to turn a hash into HTTP parameters?

... a good example: require 'rack' Rack::Utils.build_query( authorization_token: "foo", access_level: "moderator", previous: "index" ) # => "authorization_token=foo&access_level=moderator&previous=index" It even handles arrays: Rack::Utils.build_query( {:a => "a", :b => ["c...
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Does Parallel.ForEach limit the number of active threads?

...s, based on how many you physically have and how many are already busy. It allocates work for each core and then uses a technique called work stealing to let each thread process its own queue efficiently and only need to do any expensive cross-thread access when it really needs to. Have a look at t...
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Can you attach a UIGestureRecognizer to multiple views?

...matically UITapGestureRecognizer *tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(didPressed:)]; [self.view1 addGestureRecognizer:tapRecognizer]; [self.view2 addGestureRecognizer:tapRecognizer]; Output view1 has no gesture recognizers array ; view2 has got ges...
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How to write a scalable Tcp/Ip based server

.... The main feature of these enhancements is the avoidance of the repeated allocation and synchronization of objects during high-volume asynchronous socket I/O. The Begin/End design pattern currently implemented by the System.Net.Sockets..::.Socket class requires a System..::.IAsyncResult object be ...
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Efficient way to remove ALL whitespace from String?

...planation as to what this expression means, \s means "match any whitespace token", and + means "match one or more of the proceeding token". Also RegExr is a nice website to practice writing RegEx expressions with, if you want to experiment. – jrh Oct 31 '17 at...
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UIImagePickerController error: Snapshotting a view that has not been rendered results in an empty sn

...ion code - (void)showcamera { imagePicker = [[UIImagePickerController alloc] init]; [imagePicker setDelegate:self]; [imagePicker setSourceType:UIImagePickerControllerSourceTypeCamera]; [imagePicker setAllowsEditing:YES]; [self presentModalViewController:imagePicker animated:YES...