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Why can't variables be declared in a switch statement?
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Case statements are only labels. This means the compiler will interpret this as a jump directly to the label. In C++, the problem here is one of scope. Your curly brackets define the scope as everything inside the switch statement. This means that you are left with a scope where a jump ...
Memory footprint of Haskell data types
...= Uno a
data Due = Due a b
an Uno takes 2 words, and a Due takes 3.
The Int type is defined as
data Int = I# Int#
now, Int# takes one word, so Int takes 2 in total. Most unboxed types take one word, the exceptions being Int64#, Word64#, and Double# (on a 32-bit machine) which take 2. GHC act...
How can I get nth element from a list?
...untime error. It could very easily be avoided if !! had the type [a] -> Int -> Maybe a. The very reason we have Haskell is to avoid such runtime errors!
– worldsayshi
Apr 14 '15 at 21:08
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Why can I not push_back a unique_ptr into a vector?
... guarantees that a single unique_ptr container has ownership of the held pointer. This means that you can't make copies of a unique_ptr (because then two unique_ptrs would have ownership), so you can only move it.
Note, however, that your current use of unique_ptr is incorrect. You cannot use it ...
How does delete[] “know” the size of the operand array?
...his information should not be available to the programmer. I can pass a pointer to a function and free it, but to get the size myself in that same function I have to pass around an extra parameter. Does that make any sense?
– Mark Ruzon
Jun 11 '09 at 0:16
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Square retrofit server mock for testing
...new Retrofit.Builder()
// Using custom Jackson Converter to parse JSON
// Add dependencies:
// com.squareup.retrofit:converter-jackson:2.0.0-beta2
.addConverterFactory(JacksonConverterFactory.crea...
Possible to iterate backwards through a foreach?
...also an essential part of modern iterator-based programming. Perhaps the point is that it would be clearer/safer if there were two distinct keywords, to clarify whether one is asserting that the iterations are order-independent? [Given a language like Eiffel that can propagate contracts, such assert...
Differences in boolean operators: & vs && and | vs ||
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Those are the bitwise AND and bitwise OR operators.
int a = 6; // 110
int b = 4; // 100
// Bitwise AND
int c = a & b;
// 110
// & 100
// -----
// 100
// Bitwise OR
int d = a | b;
// 110
// | 100
// -----
// 110
System.out.println(c); // 4
System.out.pr...
Static variables in member functions
...A::foo() is a non-template function. There will be only one copy of static int i inside the program.
Any instance of A object will affect the same i and lifetime of i will remain through out the program. To add an example:
A o1, o2, o3;
o1.foo(); // i = 1
o2.foo(); // i = 2
o3.foo(); // i = 3
o1.f...
What is the most efficient Java Collections library? [closed]
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I've worked on quite a few data intensive projects where collections were a huge bottleneck. Java Collections are terribly inefficient (both memory and speed) especially if they store primitives.
– Jay Askren
Sep 25 '...