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Returning a C string from a function
...
Your function signature needs to be:
const char * myFunction()
{
return "My String";
}
Background:
It's so fundamental to C & C++, but little more discussion should be in order.
In C (& C++ for that matter), a string is just an array of bytes terminate...
C pointers : pointing to an array of fixed size
... an array to a function is by using a pointer-to-array parameter
void foo(char (*p)[10]);
(in C++ language this is also done with references
void foo(char (&p)[10]);
).
This will enable language-level type checking, which will make sure that the array of exactly correct size is supplied a...
How can I remove duplicate rows?
...
Assuming no nulls, you GROUP BY the unique columns, and SELECT the MIN (or MAX) RowId as the row to keep. Then, just delete everything that didn't have a row id:
DELETE FROM MyTable
LEFT OUTER JOIN (
SELECT MIN(RowId) as RowId, Col1, Col2, Col3
FROM MyTable
GROUP BY Co...
Convert Rows to columns using 'Pivot' in SQL Server
...9, 3, 87);
If your values are known, then you will hard-code the query:
select *
from
(
select store, week, xCount
from yt
) src
pivot
(
sum(xcount)
for week in ([1], [2], [3])
) piv;
See SQL Demo
Then if you need to generate the week number dynamically, your code will be:
DECLARE @c...
What does “dereferencing” a pointer mean?
...he pointer may be relative to some specific memory area, which the CPU may select based on CPU "segment" registers or some manner of segment id encoded in the bit-pattern, and/or looking in different places depending on the machine code instructions using the address.
For example, an int* properly ...
std::wstring VS std::string
...s between std::string and std::wstring . I know wstring supports wide characters such as Unicode characters. I have got the following questions:
...
How do you bind an Enum to a DropDownList control in ASP.NET?
...t; o.EnumProperty, Enum.GetValues(typeof(enumtype)).Cast<enumtype>().Select(x => new SelectListItem { Text = x.ToString(), Value = ((int)x).ToString() }))
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Get string character by index - Java
I know how to work out the index of a certain character or number in a string, but is there any predefined method I can use to give me the character at the nth position? So in the string "foo", if I asked for the character with index 0 it would return "f".
...
Why unsigned integer is not available in PostgreSQL?
...< 65536);
Here is what psql gives when I try to abuse the type.
DS1=# select (346346 :: uint2);
ERROR: value for domain uint2 violates check constraint "uint2_check"
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