Dimensional Data

In modern C++, the filesystem library allows portable interaction with directories and directory-like structures providing functions such as listing directory contents and moving files. After the C++17 standard, the contents of the Filesystems Technical Specification are now part of modern C++ and are implemented in the filesystem library. What Is the filesystems library in C++ 17? The Filesystem Library is defined in the  header (as a std::filesystem namespace), it provides operations on file systems and their components, such as paths, regular files, and directories. This library allows portable interaction with directories and directory-like structures by using classes and non-member functions. It is modernized well for C++, it is largely modeled on POSIX, and flexible enough to be implementable for different operating systems. After the C++17 standard, the contents of the Filesystems Technical Specification are now part of modern C++ and are implemented in the filesystem library. The filesystem library was previously being used by the boost.filesystem which was published in 2015. In C++17, they merged this library into modern C++. Note that, the boost implementation libraries are still available on more compilers and platforms for many benefits. The filesystem library consists of a lot of file operations (copy, move, permissions), directory operations (listing, iterating, …), and path operations. Some of classes are path, directory_entry, directory_iterator, perms, file_status, … and some of non-member functions in this library are copy, copy_file, current_path, exists, file_size, rename, remove, status, is_directory, is_empty, … Are there some examples of how to use the filesystems library in C++? Here are some examples that can be used with C++17 and standards beyond it, How can I use std::filesystem::current_path in C++ 17? In C++17, we can use std::filesystem::current_path to get current path on runtime. Here is a simple filesystem example in modern C++ that you can get current path.   #include #include   int main() {   std::cout

In programming, one of the most used variable types are text strings, and they are sometimes really important when storing and retrieving valuable data. It is important to store your data safely in its language and localization. Most programming languages have issues when storing texts and letters. In C++, there is very old well-known string type (arrays of chars) and modern types of std::basic_string types such as std::string, and std::wstring. In addition to these modern string types, C++ Builder has another amazing string feature, UnicodeString. In this post, we explain what a basic string and UnicodeString are in modern C++ and how to use them. What are the string types in C++? In general there are 3 type of alphanumeric string declarations in C++; Array of chars (See Fundamental Types)chars are shaped in ASCII forms which means each character has 1 byte (8 bits) size (that means you have 0 to 255 characters) Basic String (std::basic_string)The basic_string (std::basic_string and std::pmr::basic_string) is a class template that stores and manipulates sequences of alpha numeric string objects (char, w_char,…). A basic string can be used to define string, wstring, u8string, u16string and u32string data types. String or UnicodeStringThe UnicodeString string type is a default String type of RAD Studio, C++ Builder, Delphi that is in UTF-16 format that means characters in UTF-16 may be 2 or 4 bytes. In C++ Builder and Delphi; Char and PChar types are now WideChar and PWideChar, respectively. There is a good article about Unicode in RadStudio. In addition, there were some old string types that we used in C++ Builder and Delphi before, AnsiStringPreviously, String was an alias for AnsiString. For RAD Studio, C++ Builder and Delphi, the format of AnsiString has changed. CodePage and ElemSize fields have been added. This makes the format for AnsiString identical for the new UnicodeString. WideStringWideStrings were previously used for Unicode character data. Its format is essentially the same as the Windows BSTR. WideString is still appropriate for use in COM applications. What is basic_string? The basic_string (std::basic_string and std::pmr::basic_string) is a class template that stores and manipulates sequences of alpha numeric string objects (char, w_char,…). For example, str::string and std::wstring are the data types defined by the std::basic_string. In other words, basic_string is used to define different data_types which means a basic_string is not a string only, it is a namespace for a general string format. A basic string can be used to define string, wstring, u8string, u16string and u32string data types. The basic_string class is dependent neither on the character type nor on the nature of operations on that type. The definitions of the operations are supplied via the Traits template parameter (i.e. a specialization of std::char_traits) or a compatible traits class. The basic_string  stores the elements contiguously. Several string types for common character types are provided by basic string definitions as below. String Type Basic String Definition Standard std::string std::basic_string std::wstring std::basic_string std::u8string std::basic_string (C++20) std::u16string std::basic_string (C++11) std::u32string std::basic_string (C++11) Several string type in std::pmr namespace for common character types are provided by the basic string definitions too. Here are more details about basic string types and their literals. Note that you can use both std::basic_string (std::string, std::wstring, std::u16string, …) and UnicodeString in C++ Builder. Here are more details about basic string types and their literals. What is UnicodeString (String) in C++ Builder? The Unicode standard for UnicodeString provides a unique number for every character (8, 16 or 32 bits) more […]

The math library  in C language is designed to be used in mathematical operations. From the first C language to the latest C++ Builder 12, there have been many changes and improvements in both hardware and software. We were able to use this math.h library in C++ applications. After the C++17 standard, this library is modernized in the cmath library, Functions are declared in  header for compatibility reasons in modern C++. In this post, we explain what are the math.h and cmath libraries. What is the math.h math library in C++? In the early days of computers there was an FPU (Floating Point Unit) in addition to a CPU (Central Processing Unit). While the CPUs were slower in floating point operations (especially in trigonometric functions) FPUs were faster than CPUs in those days. The math library  in the C language is designed to be used in mathematical operations with these FPUs and CPUs. From the first C language to the latest CLANG C++ compiler, there have been many changes and improvements in both hardware and software. We were able to use this math.h library in C++ applications. The math library library functions are declared in math.h header file and it is in the standard library of the C programming language. Most of the functions are trigonometric and basic math functions, and they mostly use floating point numbers such as float, double, or long double variables. Trigonometric functions use radians in angular parameters and all functions take doubles for floating-point arguments unless otherwise specified. In C++ (C++98, C++11, C++14), these C functions were begin used by the same header . For example, if you want to use sin(), cos(), tan(), exp(), log(), and pow() functions you have to add library to the C and C++11, C++14 applications. Note that, some mathematical library functions that operate on integers are instead specified in the  header, such as abs, labs, div, and ldiv. Here is a simple C example using the sin function.   #include #include   int main() { double x = sin(1.0); }   What is the cmath mathematical special functions library in C++? In C++11 and C++14, we were able to use the math.h library in C++ applications. After the C++17 standard, this library is modernized in the cmath library, and functions are declared in  header for compatibility reasons in modern C++, and the is an optional old header to support some old codes. The CMath Mathematical Special Functions Header  defines mathematical functions and symbols in the std namespace, and previous math functions are also included, it may also define them in the global namespace. You have to add a std namespace with using namespace std; or you should use the std:: prefix for each math function. Some of the mathematical special functions are added to the C++17 cmath library header by the contents of the former international standard ISO/IEC 29124:2010 and math.h functions added too. These are only available in namespace std. If you do not use namespace you should add std:: prefix to use these modern math functions. Here is a simple C++ example using the sin function.   #include #include   int main() { double x = std::sin(1.0); }   What is the difference between math.h and cmath in modern C++? The CMath Mathematical Special Functions Header  defines mathematical functions and symbols in the std namespace, and previous math functions are also […]