How to convert string to char array in C++?
Simplest way I can think of doing it is: For safety, you might prefer: or could be in this fashion:
Simplest way I can think of doing it is: For safety, you might prefer: or could be in this fashion:
Note that there is no standard C API for milliseconds, so (on Unix) you will have to settle for usleep, which accepts microseconds:
Compiling a C++ program takes place in several steps, as specified by 2.2 (credits to Keith Thompson for the reference): The precedence among the syntax rules of translation is specified by the following phases [see footnote]. Physical source file characters are mapped, in an implementation-defined manner, to the basic source character set (introducing new-line characters for end-of-line indicators) … Read more
DWORD is not a C++ type, it’s defined in <windows.h>. The reason is that DWORD has a specific range and format Windows functions rely on, so if you require that specific range use that type. (Or as they say “When in Rome, do as the Romans do.”) For you, that happens to correspond to unsigned int, but that might not … Read more
Here is how I understood not just what virtual functions are, but why they’re required: Let’s say you have these two classes: In your main function: So far so good, right? Animals eat generic food, cats eat rats, all without virtual. Let’s change it a little now so that eat() is called via an intermediate function (a trivial function just … Read more
A pointer can be re-assigned:int x = 5; int y = 6; int *p; p = &x; p = &y; *p = 10; assert(x == 5); assert(y == 10); A reference cannot be re-bound, and must be bound at initialization:int x = 5; int y = 6; int &q; // error int &r = x; … Read more
The standard library includes the ordered and the unordered map (std::map and std::unordered_map) containers. In an ordered map the elements are sorted by the key, insert and access is in O(log n). Usually the standard library internally uses red black trees for ordered maps. But this is just an implementation detail. In an unordered map insert and access is in … Read more
The standard library includes the ordered and the unordered map (std::map and std::unordered_map) containers. In an ordered map the elements are sorted by the key, insert and access is in O(log n). Usually the standard library internally uses red black trees for ordered maps. But this is just an implementation detail. In an unordered map insert and access is in … Read more
for arrays (which is what you want) or for single elements. But it’s more simple to use vector, or use smartpointers, then you don’t have to worry about memory management. L.data() gives you access to the int[] array buffer and you can L.resize() the vector later. L.get() gives you a pointer to the int[] array.
0L is a long integer value with all the bits set to zero – that’s generally the definition of 0. The ~ means to invert all the bits, which leaves you with a long integer with all the bits set to one. In two’s complement arithmetic (which is almost universal) a signed value with all bits set to one is -1. The reason for … Read more