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Calling C++ class methods via a function pointer
...ion pointer and initialize to NULL
int (TMyClass::*pt2ConstMember)(float, char, char) const = NULL;
// C++
class TMyClass
{
public:
int DoIt(float a, char b, char c){ cout << "TMyClass::DoIt"<< endl; return a+b+c;};
int DoMore(float a, char b, char c) const
{ cout <&...
In C/C++ what's the simplest way to reverse the order of bits in a byte?
...
This should work:
unsigned char reverse(unsigned char b) {
b = (b & 0xF0) >> 4 | (b & 0x0F) << 4;
b = (b & 0xCC) >> 2 | (b & 0x33) << 2;
b = (b & 0xAA) >> 1 | (b & 0x55) << 1;
retu...
Set a persistent environment variable from cmd.exe
... value)
Dim wu
Set wu = wsh.Environment(typey)
wui = wu.Item(vary)
Select Case action
Case "ls"
WScript.Echo wui
Case "del"
On Error Resume Next
wu.remove(vary)
On Error Goto 0
Case "set"
wu.Item(vary) = value
Case "add"
If wui = "" Then
...
Why is “while ( !feof (file) )” always wrong?
...e is again std::cin, just as before.
POSIX, write(2) to flush a buffer:
char const * p = buf;
ssize_t n = bufsize;
for (ssize_t k = bufsize; (k = write(fd, p, n)) > 0; p += k, n -= k) {}
if (n != 0) { /* error, failed to write complete buffer */ }
The result we use here is k, the numb...
How to get current path with query string using Capybara
...
I know an answer has been selected, but I just wanted to give an alternative solution. So:
To get the path and querystring, like request.fullpath in Rails, you can do:
URI.parse(current_url).request_uri.should == people_path(:search => 'name')
...
__FILE__ macro shows full path
...lity tool would be careful to split file names at both slash and backslash characters to avoid any problems for folks that do manage to use /.
– RBerteig
Sep 13 '12 at 20:53
...
Why do we always prefer using parameters in SQL statements?
I am very new to working with databases. Now I can write SELECT , UPDATE , DELETE , and INSERT commands. But I have seen many forums where we prefer to write:
...
Extract month and year from a zoo::yearmon object
...an extract the date parts as required:
> format(date1, "%b") ## Month, char, abbreviated
[1] "Mar"
> format(date1, "%Y") ## Year with century
[1] "2012"
> format(date1, "%m") ## numeric month
[1] "03"
These are returned as characters. Where appropriate, wrap in as.numeric() if you want t...
INSERT INTO…SELECT for all MySQL columns
... manual. Try this:
INSERT INTO this_table_archive (col1, col2, ..., coln)
SELECT col1, col2, ..., coln
FROM this_table
WHERE entry_date < '2011-01-01 00:00:00';
If the id columns is an auto-increment column and you already have some data in both tables then in some cases you may want to omit t...
The new keyword “auto”; When should it be used to declare a variable type? [duplicate]
...e individual octets of the address (e.g., representing each as an unsigned char), so we end up with something like octets[0] & mask[0]. Thanks to C's type promotion rules, even if both operands are unsigned chars, the result is typically going to be int. We need the result to be an unsigned char...