double pow(double, int); hasn’t been removed from the spec. It has simply been reworded. It now lives in [c.math]/p11. How it is computed is an implementation detail. The only C++03 signature that has changed is: float pow(float, int); This now returns double: double pow(float, int); And this change was done for C compatibility. Clarification: 26.8 … Read more
Only partially. C++11 <string> has std::to_string for the built-in types: [n3290: 21.5/7]: string to_string(int val); string to_string(unsigned val); string to_string(long val); string to_string(unsigned long val); string to_string(long long val); string to_string(unsigned long long val); string to_string(float val); string to_string(double val); string to_string(long double val); Returns: Each function returns a string object holding the character representation … Read more
I’ll refer to the C standard; I think the C++ standard inherits the rules for <stdint.h> / <cstdint> from C. I know that gcc implements 128-bit signed and unsigned integers, with the names __int128 and unsigned __int128 (__int128 is an implementation-defined keyword) on some platforms. Even for an implementation that provides a standard 128-bit type, … Read more
The short answer is “because C++ has moved on”. Yes, back in the late 70’s, Stroustrup intended to create an upgraded C with OOP capabilities, but that is a long time ago. By the time the language was standardized in 1998, it was no longer an OOP language. It was a multi-paradigm language. It certainly … Read more
getchar() is a standard function that gets a character from the stdin. getch() is non-standard. It gets a character from the keyboard (which may be different from stdin) and does not echo it.
Interesting little question. According to the C++11 standard, sect. 21.4.2.9, basic_string(const charT* s, const Allocator& a = Allocator()); Requires: s shall not be a null pointer. Since the standard does not ask the library to throw an exception when this particular requirement is not met, it would appear that passing a null pointer provoked undefined … Read more
It’s the other way around. When ios::ate is set, the initial position will be the end of the file, but you are free to seek thereafter. When ios::app is set, all output operations are performed at the end of the file. Since all writes are implicitly preceded by seeks, there is no way to write … Read more
It means not found. It is usually defined like so: static const size_t npos = -1; It is better to compare to npos instead of -1 because the code is more legible.
To link C++ code, you need to use the g++ command, not the gcc command. When compiling, the gcc command knows that it’s compiling C++ code because of the .cpp suffix (but it’s a good idea to use the g++ command anyway). When linking, the gcc command just sees a bunch of .o files. The … Read more
A: Almost always [use a vector instead of an array]. Vectors are efficient and flexible. They do require a little more memory than arrays, but this tradeoff is almost always worth the benefits. That’s an over-simplification. It’s fairly common to use arrays, and can be attractive when: the elements are specified at compile time, e.g. … Read more