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In what cases do I use malloc and/or new?
...
malloc is not typesafe in any meaningful way. In C++ you are required to cast the return from void*. This potentially introduces a lot of problems:
#include <stdlib.h>
struct foo {
double d[5];
};
int main() {
foo *f1 = malloc(1); // error, no cast
foo *f2 = static_cast<foo*>...
Convert char to int in C and C++
... code, you can write
char a = 'a';
int ia = (int)a;
/* note that the int cast is not necessary -- int ia = a would suffice */
to convert the character '0' -> 0, '1' -> 1, etc, you can write
char a = '4';
int ia = a - '0';
/* check here if ia is bounded by 0 and 9 */
Explanation:
a - '0'...
What is the proper way to check for null values?
... @BlackBear but the value returned is most probably a string, so the cast is valid
– Firo
Mar 20 '12 at 14:29
Th...
What's the strangest corner case you've seen in C# or .NET? [closed]
... All the methods are overridden, except GetType() which can't be; so it is cast (boxed) to object (and hence to null) to call object.GetType()... which calls on null ;-p
Update: the plot thickens... Ayende Rahien threw down a similar challenge on his blog, but with a where T : class, new():
priv...
Generate class from database table
...eName'
declare @Result varchar(max) = 'public class ' + @TableName + '
{'
select @Result = @Result + '
public ' + ColumnType + NullableSign + ' ' + ColumnName + ' { get; set; }
'
from
(
select
replace(col.name, ' ', '_') ColumnName,
column_id ColumnId,
case typ.name...
Type erasure techniques
...ght type is returned
T*& operator[](size_t i) { return reinterpret_cast<T*&>(Vector<void*>::operator[](i)); }
};
As you can see, we have a strongly typed container but Vector<Animal*>, Vector<Dog*>, Vector<Cat*>, ..., will share the same (C++ and binary) c...
Why do we need virtual functions in C++?
...eclaration and calls in a main function etc. Pointer-to-derived implicitly casts to pointer-to-base (more specialized implicitly casts to more general). Visa-versa you need an explicit cast, usually a dynamic_cast. Anything else - very prone to undefined behavior so make sure you know what you're do...
Method Overloading for null argument
... an explicit "null" (yet implicit null type) argument always unambiguously selects a specific overload ??
– peterk
Jul 18 '17 at 21:43
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Java Name Hiding: The Hard Way
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You can cast a null to the type and then invoke the method on that (which will work, since the target object isn't involved in invocation of static methods).
((net.foo.X) null).doSomething();
This has the benefits of
being side-...
How to convert an array to object in PHP?
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In the simplest case, it's probably sufficient to "cast" the array as an object:
$object = (object) $array;
Another option would be to instantiate a standard class as a variable, and loop through your array while re-assigning the values:
$object = new stdClass();
foreach ...