The header <stddef.h> defines a type ptrdiff_t that is large enough to hold the signed difference of two pointer values.If we were being very cautious, however, we would use size_t for the return type of strlen, to match the standard library version. size_t is the unsigned integer type returned by the sizeof operator.)


std::cout << std::setw(5) << std::setfill('0') << zipCode << std::endl


C++ File
In C++, files are mainly dealt by using three classes fstream, ifstream, ofstream available in fstream headerfile.