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Likelihood of collision using most significant bits of a UUID in Java
...iqueness across many machines, you could have a central database table for allocating unique ids, or even batches of unique ids.
If you just need to have uniqueness in one app you can just have a counter (or a counter which starts from the currentTimeMillis()*1000 or nanoTime() depending on your r...
Where's the difference between setObject:forKey: and setValue:forKey: in NSMutableDictionary?
...voids the confusion: ` NSMutableDictionary *myDict = [[NSMutableDictionary alloc] init]; myDict[myKey] = myValue; `
– tomacco
Sep 1 at 11:07
...
'float' vs. 'double' precision
... exponent and significand). The IEEE 754 standard (used by most compilers) allocate relatively more bits for the significand than the exponent (23 to 9 for float vs. 52 to 12 for double), which is why the precision is more than doubled.
1: Section 5.2.4.2.2 ( http://www.open-std.org/jtc1/sc22/wg14/...
How would one write object-oriented code in C? [closed]
...takes uninitialized memory
struct stack * (* operator_new)(); // This allocates a new struct, passes it to construct, and then returns it
void (*push)(struct stack * this, thing * t); // Pushing t onto this stack
thing * (*pop)(struct stack * this); // Pops the top thing off the stack...
Why isn't sizeof for a struct equal to the sum of sizeof of each member?
...f a (non-union) class declared without an intervening access-specifier are allocated so that later members have higher addresses within a class object"
– jfs
Apr 10 '17 at 20:40
...
How to programmatically send SMS on the iPhone?
...ssageComposeViewController *controller = [[[MFMessageComposeViewController alloc] init] autorelease];
if([MFMessageComposeViewController canSendText])
{
controller.body = @"SMS message here";
controller.recipients = [NSArray arrayWithObjects:@"1(234)567-8910", nil];
controller.messageCom...
How to destroy an object?
...to null can work in some cases, as long as nothing else is pointing to the allocated memory.
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Why can't C compilers rearrange struct members to eliminate alignment padding? [duplicate]
...and is much less time consuming than other compiler tasks such as register allocation, function inlining, constant folding, transformation of a switch statement into binary search, etc. Thus the benefits to be gained by allowing the compiler to optimize data structures appear to be less tangible tha...
Why are Where and Select outperforming just Select?
...reating a LINQ expression is cheap. Calling delegate functions is cheap. Allocating and looping over an iterator is cheap. But it's even cheaper to not do these things. Thus, if you find that a LINQ statement is the bottleneck in your program, in my experience rewriting it without LINQ will alwa...
How can I propagate exceptions between threads?
...;
try {
std::rethrow_exception(e);
} catch (const std::bad_alloc&) {
puts("Success!");
}
}
I have no idea what I was doing wrong in 2013, but I'm sure it was my fault.]
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