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What do the following phrases mean in C++: zero-, default- and value-initialization?
...) {}; ~C(); int m; }; // non-POD, default-initialising m
int main()
{
char buf[sizeof(B)];
std::memset( buf, 0x5a, sizeof( buf));
// use placement new on the memset'ed buffer to make sure
// if we see a zero result it's due to an explicit
// value initialization
B* pB =...
Best way to select random rows PostgreSQL
I want a random selection of rows in PostgreSQL, I tried this:
12 Answers
12
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How to Select Columns in Editors (Atom,Notepad++, Kate, VIM, Sublime, Textpad,etc) and IDEs (NetBean
How to select columns in Editors and IDEs to columnar delete, insert or replace some characters ?
21 Answers
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Why is SELECT * considered harmful?
Why is SELECT * bad practice? Wouldn't it mean less code to change if you added a new column you wanted?
15 Answers
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Difference between EXISTS and IN in SQL?
...way to avoid counting:
--this statement needs to check the entire table
select count(*) from [table] where ...
--this statement is true as soon as one match is found
exists ( select * from [table] where ... )
This is most useful where you have if conditional statements, as exists can be a lot ...
How to print third column to last column?
...e the same between all columns, but there have to be EXACTLY ONE delimiter character between columns. So if you are dealing with programs that align their output with delimiters, it is better to use awk.
– sknaumov
Aug 21 '12 at 12:40
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When should I use nil and NULL in Objective-C?
...ke a C pointer) in Objective-C. Like nil , NULL got no value nor address.
char *myChar = NULL;
struct MyStruct *dStruct = NULL;
So if there is a situation, when I need to check my struct (structure type variable) is empty or not then, I will use:
if (dStruct == NULL)
NSLog("The struct is emp...
Using union and order by clause in mysql
...criteria from a table based on distance for a search on my site.
The first select query returns data related to the exact place search .
The 2nd select query returns data related to distance within 5 kms from the place searched.
The 3rd select query returns data related to distance within 5-15 kms f...
Vim: faster way to select blocks of text in visual mode
I have been using vim for quite some time and am aware that selecting blocks of text in visual mode is as simple as SHIFT + V and moving the arrow key up or down line-by-line until I reach the end of the block of text that I want selected.
...
maxlength ignored for input type=“number” in Chrome
...rch, password, tel, or url, this attribute specifies the maximum number of characters (in Unicode code points) that the user can enter; for other control types, it is ignored.
So maxlength is ignored on <input type="number"> by design.
Depending on your needs, you can use the min and max at...