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Counting DISTINCT over multiple columns
... the columns, then get the distinct count of instances of the concatenated string.
SELECT count(DISTINCT concat(DocumentId, DocumentSessionId)) FROM DocumentOutputItems;
In MySQL you can do the same thing without the concatenation step as follows:
SELECT count(DISTINCT DocumentId, DocumentSessio...
When should I use the “strictfp” keyword in java?
...latform. If you don't use strictfp, the JVM implementation is free to use extra precision where available.
From the JLS:
Within an FP-strict expression, all
intermediate values must be elements
of the float value set or the double
value set, implying that the results
of all FP-strict e...
Why do assignment statements return a value?
...operty of the assignment operator is used is reading lines from a file...
string line;
while ((line = streamReader.ReadLine()) != null)
// ...
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Super-simple example of C# observer/observable with delegates
...***************/
class Program
{
static void Main(string[] args)
{
Parent p = new Parent();
}
}
////////////////////////////////////////////
public delegate void DelegateName(string data);
class Child...
How do I find files with a path length greater than 260 characters in Windows?
...-Object {
$filePath = $_.FullName
$length = $_.FullNameLength
$string = "$length : $filePath"
# Write to the Console.
if ($writeToConsoleAsWell) { Write-Host $string }
#Write to the file.
$stream.WriteLine($string)
}
$stream.Close()
...
How to get a JavaScript object's class?
...andards-compliant means of getting the "class" of a JavaScript object as a string. If the object is instantiated with var obj = new MyClass(), it will return "MyClass".
It will return "Number" for numbers, "Array" for arrays and "Function" for functions, etc. It generally behaves as expected. The o...
What happens to a declared, uninitialized variable in C? Does it have a value?
... x86-64 calling conventions:
%rdi is the first printf argument, thus the string "%d\n" at address 0x4005e4
%rsi is the second printf argument, thus i.
It comes from -0x4(%rbp), which is the first 4-byte local variable.
At this point, rbp is in the first page of the stack has been allocated by th...
How do I use extern to share variables between source files?
...
SFLAGS = -std=c11
GFLAGS = -g
OFLAGS = -O3
WFLAG1 = -Wall
WFLAG2 = -Wextra
WFLAG3 = -Werror
WFLAG4 = -Wstrict-prototypes
WFLAG5 = -Wmissing-prototypes
WFLAGS = ${WFLAG1} ${WFLAG2} ${WFLAG3} ${WFLAG4} ${WFLAG5}
UFLAGS = # Set on command line only
CFLAGS = ${SFLAGS} ${GFLAGS} ${OFLAGS} ${...
Why is quicksort better than mergesort?
....
QuickSort is more popular because it:
Is in-place (MergeSort requires extra memory linear to number of elements to be sorted).
Has a small hidden constant.
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Iterate keys in a C++ map
...e <iostream>
#include <map>
int main()
{
std::map<std::string, int> myMap;
myMap["one"] = 1;
myMap["two"] = 2;
myMap["three"] = 3;
for ( const auto &myPair : myMap ) {
std::cout << myPair.first << "\n";
}
}
...