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Is std::vector so much slower than plain arrays?
... created. What happens if we change Pixel to:
struct Pixel
{
unsigned char r, g, b;
};
Result: about 10% faster. Still slower than an array. Hm.
# ./vector
UseArray completed in 3.239 seconds
UseVector completed in 5.567 seconds
Idea #4 - Use iterator instead of loop index
How about usin...
Create objective-c class instance by name?
...runtime.h>
//Declaration in the above named file
id objc_getClass(const char* name);
//Usage
id c = objc_getClass("Object");
[ [ c alloc ] free ];
Under the Objective-C (1.0 or unnamed version) you would utilize the following:
#import <objc/objc-api.h>
//Declaration within the above name...
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
...
How do pointer to pointers work in C?
...his case, if this is the only occurrence of "hello" in memory then,
const char *c = "hello";
... defines c to be a pointer to the (read-only) string "hello", and thus contains the value 63. c must itself be stored somewhere: in the example above at location 58. Of course we can not only point to ...
How to concatenate a std::string and an int?
...tm;
sstm << name << age;
result = sstm.str();
// 7. with itoa
char numstr[21]; // enough to hold all numbers up to 64-bits
result = name + itoa(age, numstr, 10);
// 8. with sprintf
char numstr[21]; // enough to hold all numbers up to 64-bits
sprintf(numstr, "%d", age);
result = name + ...
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...
Why is MySQL's default collation latin1_swedish_ci?
... He is Finnish , but Finnish and Swedish share almost the same special characters ,so they share the same case insensitive collation
– kommradHomer
Feb 26 '14 at 10:47
5
...
Get Substring - everything before certain char
I'm trying to figure out the best way to get everything before the - character in a string. Some example strings are below. The length of the string before - varies and can be any length
...
C++对象布局及多态探索之菱形结构虚继承 - C/C++ - 清泛网 - 专注C/C++及内核技术
...
{
C041() : c_(0x01) {}
virtual void foo() { c_ = 0x02; }
char c_;
};
struct C100 : public virtual C041
{
C100() : c_(0x02) {}
char c_;
};
struct C101 : public virtual C041
{
C101() : c_(0x03) {}
char c_;
};
struct C110 : public C100, public C101 ...