大约有 22,000 项符合查询结果（耗时：0.0131秒） [XML]
Using scanf() in C++ programs is faster than using cin?
... at runtime, it usually has an advantage of not requiring excessive memory allocations (this depends on your compiler and runtime). That said, unless performance is your only end goal and you are in the critical path then you should really favour the safer (slower) methods.
There is a very deliciou...
How to Free Inode Usage?
...arge number of inodes used even if the disk is not very full.
An inode is allocated to a file so, if you have gazillions of files, all 1 byte each, you'll run out of inodes long before you run out of disk.
It's also possible that deleting files will not reduce the inode count if the files have mul...
startsWith() and endsWith() functions in PHP
...s so far seem to do loads of unnecessary work, strlen calculations, string allocations (substr), etc. The 'strpos' and 'stripos' functions return the index of the first occurrence of $needle in $haystack:
function startsWith($haystack,$needle,$case=true)
{
if ($case)
return strpos($hays...
Reference: Comparing PHP's print and echo
... a dedicated SAPI function).
Speed: echo x vs print x
Unlike echo, print allocates a temporary variable. However, the amount of time spent on this activity is minuscule, so the difference between these two language constructs is negligible.
Speed: echo a,b,c vs echo a.b.c
The first one compiles...
How to get a variable name as a string in PHP?
...ments something called "copy-on-write" so that $foo = $bar doesn't need to allocate extra memory straight away) or because they have been assigned (or passed to a function) by reference (e.g. $foo =& $bar). So a zval has no name.
When you pass a parameter to a function you are creating a new var...
PHP DateTime::modify adding and subtracting months
...ch could be a problem both supply-end (say if there is a monthly bandwidth allocation and Feb goes to waste and March gets doubled up on) and demand-end (users feel cheated out of Feb and perceive the extra March as attempt to correct mistake). On the other hand, notice that the two date sets:
neve...
ios Upload Image and Text using HTTP POST
...programmed to accept.
NSMutableDictionary* _params = [[NSMutableDictionary alloc] init];
[_params setObject:[NSString stringWithString:@"1.0"] forKey:[NSString stringWithString:@"ver"]];
[_params setObject:[NSString stringWithString:@"en"] forKey:[NSString stringWithString:@"lan"]];
[_params setObje...
Is Java really slow?
...bandwidth bound (caching, etc.) this makes it slower. The flipside is that allocation/deallocation is blazing fast (highly optimized). This is a feature of most high-level languages now, and due to objects and use of GC rather than explicit memory allocation. Plus bad library decisions.
Streams-bas...
PHP memory profiling
..., to see how much memory my data is using, and/or which function calls are allocating the most memory.
4 Answers
...
do you have kcachegrind like profiling tools for mac [closed]
...
Apple supply Instruments for monitoring runtime allocation of stuff and finding leaks, Shark for explicit profiling and Guard Malloc (directly built into Xcode) for memory allocation debugging. These all come as part of the developer tools.
...