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How do you compare structs for equality in C?
...use memcmp to compare structs for equality due to potential random padding characters between field in structs.
// bad
memcmp(&struct1, &struct2, sizeof(struct1));
The above would fail for a struct like this:
typedef struct Foo {
char a;
/* padding */
double d;
/* padding */
...
Using varchar(MAX) vs TEXT on SQL Server
...es ('b')
insert into @table values ('c')
insert into @table values ('d')
select *
from @table
where a ='a'
This give an error:
The data types text and varchar are incompatible in the equal to operator.
Wheras this does not:
declare @table table (a varchar(max))
Interestingly, LIKE still wo...
What is the best way to concatenate two vectors?
...
Depends on whether you really need to physically concatenate the two vectors or you want to give the appearance of concatenation of the sake of iteration. The boost::join function
http://www.boost.org/doc/libs/1_43_0/libs/range/doc/html/range/reference/utilities/join.html
...
Using scanf() in C++ programs is faster than using cin?
...numbers.
iostream version:
#include <iostream>
int main(int argc, char **argv) {
int parity = 0;
int x;
while (std::cin >> x)
parity ^= x;
std::cout << parity << std::endl;
return 0;
}
scanf version:
#include <stdio.h>
int main(int argc, char **a...
Omitting all xsi and xsd namespaces when serializing an object in .NET?
...e doc, when it writes it does not check for the following:
Invalid characters in attribute and element names.
Unicode characters that do not fit the specified encoding. If the Unicode
characters do not fit the specified
encoding, the XmlTextWriter does not
escape the Unicode characte...
C++使用OLE/COM高速读写EXCEL的源码 - C/C++ - 清泛网 - 专注C/C++及内核技术
...ad = FALSE);
///通过名称使用某个sheet，
BOOL LoadSheet(const TCHAR* sheet,BOOL pre_load = FALSE);
///通过序号取得某个Sheet的名称
CString GetSheetName(long table_index);
///得到Sheet的总数
int GetSheetCount();
///打开文件
BOOL OpenExcelFile(const TCHAR...
Are nested HTML comments possible?
...ere. Its parent element has to be either the <body> element or a few select others.
– John E
Jan 17 '19 at 14:09
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How to check for a valid Base64 encoded string
...s pretty easy to recognize a Base64 string, as it will only be composed of characters 'A'..'Z', 'a'..'z', '0'..'9', '+', '/' and it is often padded at the end with up to three '=', to make the length a multiple of 4. But instead of comparing these, you'd be better off ignoring the exception, if it o...
Maximum MIMEType Length when storing type in DB
...s", type (eg. "application") and subtype (eg "vnd...") both can be max 127 characters. You do the math :)
Edit: Meanwhile, that document has been obsoleted by RFC 6838, which does not alter the maximum size but adds a remark:
Also note that while this syntax allows names of up to 127
characte...
Calling Objective-C method from C++ member function?
...d );
int doSomethingWith( void * aParameter );
void logMyMessage( char * aCStr );
private:
void * self;
};
#endif
Notice the wrapper methods no longer require the void pointer to an instance of MyClass; it is now a private member of MyClassImpl. The init method is used to instantia...