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Best practices for circular shift (rotate) operations in C++
...lude <stdint.h> // for uint32_t
#include <limits.h> // for CHAR_BIT
// #define NDEBUG
#include <assert.h>
static inline uint32_t rotl32 (uint32_t n, unsigned int c)
{
const unsigned int mask = (CHAR_BIT*sizeof(n) - 1); // assumes width is a power of 2.
// assert ( (c<...
Using LINQ to concatenate strings
...bit slower, actually. Even using Aggregate with a StringBuilder instead of concatenation is slower than String.Join.
– Joel Mueller
May 7 '09 at 20:33
4
...
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...
How to display pandas DataFrame of floats using a format string for columns?
...ake_float)
Also, it can be easily used with multiple columns...
df = pd.concat([s, s * 2], axis=1)
make_floats = lambda row: "${:,.2f}, ${:,.3f}".format(row[0], row[1])
df.apply(make_floats, axis=1)
share
|
...
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 <&...
How do you get the current project directory from C# code when creating a custom MSBuild task?
...wrong for my case. This is giving me */{project}/bin folder, so I need to concat a .parent.
– Captain Prinny
Aug 1 '19 at 13:48
1
...
printf with std::string?
...style string, you can use the c_str() method of std::string to get a const char * that is null-terminated. Using your example:
#include <iostream>
#include <string>
#include <stdio.h>
int main()
{
using namespace std;
string myString = "Press ENTER to quit program!";
...
What is the meaning of “__attribute__((packed, aligned(4))) ”
...es in some cases. Consider the following structure:
typedef struct
{
char Data1;
int Data2;
unsigned short Data3;
char Data4;
}sSampleStruct;
sizeof(sSampleStruct) will be 12 rather than 8. Because of structure padding. By default, In X86, structures will be padded to 4-byte ...
C libcurl get output into a string
...
#include <string.h>
#include <curl/curl.h>
struct string {
char *ptr;
size_t len;
};
void init_string(struct string *s) {
s->len = 0;
s->ptr = malloc(s->len+1);
if (s->ptr == NULL) {
fprintf(stderr, "malloc() failed\n");
exit(EXIT_FAILURE);
}
s->pt...
Is it possible to print a variable's type in standard C++?
...f typename std::remove_reference<T>::type TR;
std::unique_ptr<char, void(*)(void*)> own
(
#ifndef _MSC_VER
abi::__cxa_demangle(typeid(TR).name(), nullptr,
nullptr, nullptr),
#else
nullptr,
#endif
...