header-files

问题 Is there any way to not have to write function declarations twice (headers) and still retain the same scalability in compiling, clarity in debugging, and flexibility in design when programming in C++? 回答1: Use Lzz. It takes a single file and automatically creates a .h and .cpp for you with all the declarations/definitions in the right place. Lzz is really very powerful, and handles 99% of full C++ syntax, including templates, specializations etc etc etc. Update 150120: Newer C++ '11/14 syntax

问题 This is probably a stupid question, but I\'ve searched for quite a while now here and on the web and couldn\'t come up with a clear answer (did my due diligence googling). So I\'m new to programming... My question is, how does the main function know about function definitions (implementations) in a different file? ex. Say I have 3 files main.cpp myfunction.cpp myfunction.hpp //main.cpp #include \"myfunction.hpp\" int main() { int A = myfunction( 12 ); ... } - //myfunction.cpp #include \

问题 I\'ve perused the possible duplicates, however none of the answers there are sinking in. tl;dr: How are source and header files related in C ? Do projects sort out declaration/definition dependencies implicitly at build time? I\'m trying to understand how the compiler understands the relationship between .c and .h files. Given these files: header.h : int returnSeven(void); source.c : int returnSeven(void){ return 7; } main.c : #include <stdio.h> #include <stdlib.h> #include \"header.h\" int

问题 I have a C++ program (.cpp) inside which I wish to use some of the functions which are present inside the C header files such as stdio.h, conio.h, stdlib.h, graphics.h, devices.h etc. I could include the stdio.h library inside my cpp file as : #include <cstdio> . How do I include the other library files? How do I add the graphics.h library? I\'m using Microsoft Visual Studio 6.0 Enterprise Edition and also Turbo C++ 3.0. 回答1: For a list of C standard C headers (stdio, stdlib, assert, ...),

问题 I have a question regarding include guards in C. I\'ve done a bit of reading but would appreciate a little bit of clarification. Let\'s say I have a header file \"header.h\" with a function definition. #ifndef HEADER_FILE #define HEADER_FILE int two(void){ return 2; } #endif This header file has an include guard. However, I\'m kind of confused as to what #define HEADER_FILE is actually doing. Let\'s say I were to forget the include guard, it would have been perfectly legal for me to

问题 I am getting a really odd error from GCC 4.8.1 with inline functions. I have two near-identical inline functions defined in header files ( debug.h and error.h ) in src/include/ , with the only difference being what they print - one prefixes DEBUG: to the message, and the other %s: error: %s (program name, error message). When defining the functions both inline, and compiling a debug build (so it sets the macro DEBUG=1 ), I get lots of undefined reference errors: src/main_debug.o gcc -osrc

问题 The C++ standard library headers may include each other in unspecified ways, so programmers generally shouldn\'t depend on one header including another. In a few cases, however, a header is guaranteed to include another header, or make available certain functions that would otherwise require inclusion of another header. What are those cases? 回答1: This answer ignores C headers - both the <meow.h> and <cmeow> ones. Of the C++ library headers (all references are to N4659): <initializer_list> is

问题 Traditionally, the standard and portable way to avoid multiple header inclusions in C++ was/is to use the #ifndef - #define - #endif pre-compiler directives scheme also called macro-guard scheme (see code snippet below). #ifndef MY_HEADER_HPP #define MY_HEADER_HPP ... #endif In most implementations/compilers (see picture below) however, there\'s a more \"elegant\" alternative that serves the same purpose as the macro-guard scheme called #pragma once. #pragma once has several advantages

问题 I am using CMake on a small C++ project and so far it works great... with one twist :x When I change a header file, it typically requires recompiling a number of sources files (those which include it, directly or indirectly), however it seems that cmake only detects some of the source files to be recompiled, leading to a corrupted state. I can work around this by wiping out the project and rebuilding from scratch, but this circumvents the goal of using a make utility: only recompiling what is

问题 There are two path separators in common use: the Unix forward-slash and the DOS backslash. Rest in peace, Classic Mac colon. If used in an #include directive, are they equal under the rules of the C++11, C++03, and C99 standards? 回答1: C99 says (§6.4.7/3): If the characters ', \, ", //, or /* occur in the sequence between the < and > delimiters, the behavior is undefined. Similarly, if the characters ', \, //, or /* occur in the sequence between the " delimiters, the behavior is undefined.