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What are the differences between a pointer variable and a reference variable in C++?
..., the lifetime of that object becomes the lifetime of the reference.
std::string s1 = "123";
std::string s2 = "456";
std::string s3_copy = s1 + s2;
const std::string& s3_reference = s1 + s2;
In this example s3_copy copies the temporary object that is a result of the concatenation. Whereas s3...
What is the purpose of Rank2Types?
...y only use it as monomorphic. In the example map uses id as if it had type String -> String. And of course you can also pass a simple monomorphic function of the given type instead of id. Without rank2types there is no way for a function to require that its argument must be a polymorphic function...
Concurrent vs serial queues in GCD
... running in background thread")
}
let imgURL = URL(string: "https://upload.wikimedia.org/wikipedia/commons/0/07/Huge_ball_at_Vilnius_center.jpg")!
let _ = try! Data(contentsOf: imgURL)
print("\(i) completed downloading")
}
}
}
Task wil...
Scala how can I count the number of occurrences in a list
... to elements so it knows how to group them. An alternative to grouping the strings in the answer by their identities could be, say, grouping by their length (groupBy(_.size)) or by their first letter (groupBy(_.head)).
– ohruunuruus
Nov 9 '16 at 15:35
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Extract a substring according to a pattern
Suppose I have a list of string:
8 Answers
8
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How can I remove a character from a string using Javascript?
...st isn't right.
All I would like to do is remove the character r from a string.
The problem is, there is more than one instance of r in the string.
However, it is always the character at index 4 (so the 5th character).
...
When to use NSInteger vs. int
...e correct format specifier you should use for each of these types, see the String Programming Guide's section on Platform Dependencies
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How do I use Java to read from a file that is actively being written to?
...ed in the console.
public class FileReader {
public static void main(String args[]) throws Exception {
if(args.length>0){
File file = new File(args[0]);
System.out.println(file.getAbsolutePath());
if(file.exists() && file.canRead()){
...
How to implement Enums in Ruby?
...e when you want to enhance readability without littering code with literal strings.
postal_code[:minnesota] = "MN"
postal_code[:new_york] = "NY"
Constants are appropriate when you have an underlying value that is important. Just declare a module to hold your constants and then declare the constan...
Which one will execute faster, if (flag==0) or if (0==flag)?
... some user declaring them: typedef, enum, struct, class. For example, std::string is user defined, even though you certainly not defined it yourself :)
– Matthieu M.
Jan 7 '11 at 14:29
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