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Converting an int to std::string
... int length = snprintf( NULL, 0, "%d", x );
assert( length >= 0 );
char* buf = new char[length + 1];
snprintf( buf, length + 1, "%d", x );
std::string str( buf );
delete[] buf;
return str;
}
You can do more with it. Just use "%g" to convert float or double to string, use "%x" to co...
Why is it slower to iterate over a small string than a small list?
...string took longer than doing the same operation on a list of small single character strings. Any explanation? It's almost 1.35 times as much time.
...
How can I efficiently select a Standard Library container in C++11?
... },
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What are transparent comparators?
...ast, works for std::string which has overloaded less than operators taking char const* as argument. Since these function objects are also new, even if they do the wrong thing (i.e. require a conversion for some type) it would, at least, not be a silent change resulting in a performance degradation.
...
What is the default initialization of an array in Java?
...t is a 0.
For float/double that is a 0.0
For booleans that is a false.
For char that is the null character '\u0000' (whose decimal equivalent is 0).
When you create an array of something, all entries are also zeroed. So your array contains five zeros right after it is created by new.
Note (based...
How do I detect unsigned integer multiply overflow?
... addcarry_u8 or subborrow_u64). Their signature is a bit obtuse:
unsigned char _addcarry_u32(unsigned char c_in, unsigned int src1, unsigned int src2, unsigned int *sum);
unsigned char _subborrow_u32(unsigned char b_in, unsigned int src1, unsigned int src2, unsigned int *diff);
c_in/b_in is the c...
In-Place Radix Sort
...though.
Btw: If you're dealing with DNA strings only: You can compress a char into two bits and pack your data quite a lot. This will cut down the memory requirement by factor four over a naiive representation. Addressing becomes more complex, but the ALU of your CPU has lots of time to spend duri...
Replace all non Alpha Numeric characters, New Lines, and multiple White Space with one Space
.../[\W_]+/g," ");
\W is the negation of shorthand \w for [A-Za-z0-9_] word characters (including the underscore)
Example at regex101.com
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How to count the number of set bits in a 32-bit integer?
...numeric_limits<T>::radix == 2, "non-binary type");
// sizeof(x)*CHAR_BIT
constexpr int bitwidth = std::numeric_limits<T>::digits + std::numeric_limits<T>::is_signed;
// std::bitset constructor was only unsigned long before C++11. Beware if porting to C++03
static_...
Why can't I initialize non-const static member or static array in class?
...e symbol if it is used in the translation unit and ensures the linker only selects and leaves one copy if it's defined in multiple translation units due to it being in a comdat group. const at file scope makes the compiler never emit a symbol because it's always substituted immediately in the code u...