大约有 42,000 项符合查询结果（耗时：0.0358秒） [XML]
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 + ...
How to get my IP address programmatically on iOS/macOS?
... @"ipv6"
- (NSString *)getIPAddress:(BOOL)preferIPv4
{
NSArray *searchArray = preferIPv4 ?
@[ /*IOS_VPN @"/" IP_ADDR_IPv4, IOS_VPN @"/" IP_ADDR_IPv6,*/ IOS_WIFI @"/" IP_ADDR_IPv4, IOS_WIFI @"/" IP_ADDR_IPv6, IOS_CELLULAR @"/" IP_ADDR_IPv4, IOS_CELLULAR @"/" IP_ADDR...
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...
How to use sed to replace only the first occurrence in a file?
... then only looked for starting on the next line. Therefore, both lines are selected in this case, and the s/foo/bar/ substitution is performed on both of them.
sed '1,/foo/ s//bar/' <<<$'1foo\n2foo\n3foo' fails: with sed: first RE may not be empty (BSD/macOS) and sed: -e expression #1, char...
How to enter a multi-line command
...e grave accent (backtick):
Get-ChildItem -Recurse `
-Filter *.jpg `
| Select LastWriteTime
However, this is only ever necessary in such cases as shown above. Usually you get automatic line continuation when a command cannot syntactically be complete at that point. This includes starting a new...
invalid multibyte char (US-ASCII) with Rails and Ruby 1.9
...ave you tried adding a magic comment in the script where you use non-ASCII chars? It should go on top of the script.
#!/bin/env ruby
# encoding: utf-8
It worked for me like a charm.
share
|
impro...
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!";
...
Use C++ with Cocoa Instead of Objective-C?
...ving it an extension of .mm, or by right-clicking on the file in Xcode and selecting Get Info > General then changing the File Type to sourcecode.cpp.objcpp. The second option is useful if you have a .cpp file where you want to use Objective-C within a Mac-specific #ifdef.
...
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<...
How to check if a String contains only ASCII?
The call Character.isLetter(c) returns true if the character is a letter. But is there a way to quickly find if a String only contains the base characters of ASCII?
...