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How do you know when to use fold-left and when to use fold-right?
... // third stack frame
// (I don't remember if the JVM allocates space
// on the stack for the third frame as well)
while List(1,2,3).foldLeft(0)(_ + _) would reduce to:
(((0 + 1) + 2) + 3)
which can be iteratively computed, as done in the implementation of List.
In a str...
Should 'using' directives be inside or outside the namespace?
...ler errors. However, it is unclear which version of the Guid type is being allocated. If the using directive is moved inside of the namespace, as shown below, a compiler error will occur:
namespace Microsoft.Sample
{
using Guid = System.Guid;
public class Guid
{
public Guid(stri...
Are there disadvantages to using a generic varchar(255) for all text-based fields?
...
It's good practice to allocate only a little over what you need. Phone numbers would never go this large.
One reason is that unless you validate against large entries, no doubt someone will use all there is. Then you might run out of space in...
Is pass-by-value a reasonable default in C++11?
... especially around memory management (in the event that the object is heap-allocated)
4 Answers
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In a storyboard, how do I make a custom cell for use with multiple controllers?
...k at the class of the cell, as defined in the cell's nib. Call [[CellClass alloc] initWithCoder:].
The -initWithCoder: method goes through and adds subviews and sets properties that were defined in the nib. (IBOutlets probably get hooked up here as well, though I haven't tested that; it may happen i...
Understanding Canvas and Surface concepts
...seen.
A Bitmap is just an interface to some pixel data. The pixels may be allocated by Bitmap itself when you are directly creating one, or it may be pointing to pixels it doesn't own such as what internally happens to hook a Canvas up to a Surface for drawing. (A Bitmap is created and pointed to ...
When should we use mutex and when should we use semaphore
...have to carefully track who currently has responsibility for it, much like allocated memory).
So, if you have a number of instances of a resource (say three tape drives), you could use a semaphore with a count of 3. Note that this doesn't tell you which of those tape drives you have, just that you ...
Why are preprocessor macros evil and what are the alternatives?
...to wrap a function with macros to pass on file/line information:
#define malloc(x) my_debug_malloc(x, __FILE__, __LINE__)
#define free(x) my_debug_free(x, __FILE__, __LINE__)
Now we can use my_debug_malloc as the regular malloc in the code, but it has extra arguments, so when it comes to the end...
Regular cast vs. static_cast vs. dynamic_cast [duplicate]
... // 4 bytes
Since this results in a 4-byte pointer pointing to 1 byte of allocated memory, writing to this pointer will either cause a run-time error or will overwrite some adjacent memory.
*p = 5; // run-time error: stack corruption
In contrast to the C-style cast, the static cast will allow t...
Is there any way to put malicious code into a regular expression?
...ime–space trade‐off.
With a DFA, you spend more time building it (and allocating more states), whereas with an NFA you spend more time executing it, since it can be multiple states at the same time, and backtracking can eat your lunch — and your CPU.
Denial‐of‐Service Solutions
Probably...