The conio.h header is specific to Turbo C, which predates the earliest C standard by several years. It contains routines that are specific to the DOS command line. One function here that’s frequently used is getch, which allows reading one character at a time without having to press the Enter key. It also contains gotoxy which allows placing … Read more
and Are just the same thing. so does: And once you declared the reference, you can think of it just like the actual variable itself. so you don’t need particular operator to dereference it. when passing variables through function arguments, the raw object is always shallow copied in memory to the new variable in the … Read more
You need to make use of the begin and end method of the vector class, which return the iterator referring to the first and the last element respectively.
How is it a keyword and an instance of a type? This isn’t surprising. Both true and false are keywords and as literals they have a type ( bool ). nullptr is a pointer literal of type std::nullptr_t, and it’s a prvalue (you cannot take the address of it using &). 4.10 about pointer conversion says that a prvalue of type std::nullptr_t is a null pointer constant, and that an … Read more
Private members are only accessible within the class defining them. Protected members are accessible in the class that defines them and in classes that inherit from that class. Edit: Both are also accessible by friends of their class, and in the case of protected members, by friends of their derived classes. Edit 2: Use whatever … Read more
Depends on what you want to do: to read the value as an ascii code, you can write to convert the character ‘0’ -> 0, ‘1’ -> 1, etc, you can write Explanation:a – ‘0’ is equivalent to ((int)a) – ((int)’0′), which means the ascii values of the characters are subtracted from each other. Since 0 comes directly before 1 in the ascii … Read more
I’m not a huge fan of turning on exceptions for iostreams. I/O errors aren’t exceptional enough, in that errors are often very likely. I prefer only to use exceptions for less frequent error conditions. The code isn’t bad, but skipping 80 characters is a bit arbitrary, and the error variable isn’t necessary if you fiddle … Read more
It’s a syntax for array references – you need to use (&array) to clarify to the compiler that you want a reference to an array, rather than the (invalid) array of references int & array[100];. EDIT: Some clarification. These three are different ways of declaring the same function. They’re all treated as taking an int * parameter, you can pass … Read more
Checking if v contains the element x: Checking if v contains elements (is non-empty):
The main function must be declared as a non-member function in the global namespace. This means that it cannot be a static or non-static member function of a class, nor can it be placed in a namespace (even the unnamed namespace). The name main is not reserved in C++ except as a function in the … Read more