header-files

问题 Consider a pair of two source files: an interface declaration file ( *.h or *.hpp ) and its implementation file ( *.cpp ). Let the *.h file be like the following: namespace MyNamespace { class MyClass { public: int foo(); }; } I have seen two different practices for using namespaces in source files: *.cpp showing practice #1: #include "MyClass.h" using namespace MyNamespace; int MyClass::foo() { ... } *.cpp showing practice #2: #include "MyClass.h" namespace MyNamespace { int MyClass::foo() {

问题 I made program like this. 1 #include <stdio.h> 2 #include <string.h> 3 #include <stdlib.h> 4 #include "libavformat/avformat.h" 5 6 int main (int argc, char* argv[]){ 7 av_register_all(); 8 return 0; 9 } My header file located in root@ubuntu:/home/juneyoungoh/getDuration# find / -name "avformat.h" /root/ffmpeg/libavformat/avformat.h /usr/local/include/libavformat/avformat.h then I run with gcc getDuration.c , but I show message like below. root@ubuntu:/home/juneyoungoh/getDuration# gcc

问题 In GIMP, you're able to save an image as a C header file. I did so with an XPM file, which looks like the image below: If I were to save the XPM image as a C header file, GIMP will output this C header file. In order to process each pixel of the given image data, the header pixel is called repeatedly. What I don't understand is what the header pixel does to process the data in the first place. #define HEADER_PIXEL(data,pixel) {\ pixel[0] = (((data[0] - 33) << 2) | ((data[1] - 33) >> 4)); \

问题 This question already has an answer here : One definition rule and different class definitions in two translation units (1 answer) Closed 6 years ago . For example I have 2 cpp files: f1.cpp and f2.cpp, and also a header file: xxx.h. f1.cpp has the following source code: #include <iostream> #include "xxx.h" using namespace std; int main () { rect rplace; polar pplace; cout<<"Enter the x and y values: "; while (cin>>rplace.x>>rplace.y) { pplace=rect_to_polar(rplace); show_polar(pplace); cout<<

问题 This question already has an answer here : One definition rule and different class definitions in two translation units (1 answer) Closed 6 years ago . For example I have 2 cpp files: f1.cpp and f2.cpp, and also a header file: xxx.h. f1.cpp has the following source code: #include <iostream> #include "xxx.h" using namespace std; int main () { rect rplace; polar pplace; cout<<"Enter the x and y values: "; while (cin>>rplace.x>>rplace.y) { pplace=rect_to_polar(rplace); show_polar(pplace); cout<<

问题 I am trying to compile some C code (called rand_beta) in terminal which contains the lines to include R.h and Rmath.h header files using gcc -o rand_beta rand_beta.c so I can then call the code from within R. However, I get the error messages: rand_beta.c:1:15: error: R.h: No such file or directory rand_beta.c:2:19: error: Rmath.h: No such file or directory It seems that these header files which should come installed with R are not on my system. Can someone guide me as to how I can get my

问题 I have written a Makefile to compile an openCV program on OSX (more general in Unix systems). The code has a header named constants.hpp where some constants are defined. I would like to make the Makefile recompile the program when this header file changes because the values of the constants in it change the program behavior. My Makefile is the following CPP = g++ CPPFLAGS = -std=c++11 all: main.o main.o: main.cpp $(CPP) $^ $(CPPFLAGS) -o $@ Searching around I tried to define after CPPFLAGS

问题 I'm looking to create two classes, each of which contains an object of the other class type. How can I do this? If I can't do this, is there a work-around, like having each class contain a pointer to the other class type? Thanks! Here's what I have: File: bar.h #ifndef BAR_H #define BAR_H #include "foo.h" class bar { public: foo getFoo(); protected: foo f; }; #endif File: foo.h #ifndef FOO_H #define FOO_H #include "bar.h" class foo { public: bar getBar(); protected: bar b; }; #endif File:

问题 I'm looking to create two classes, each of which contains an object of the other class type. How can I do this? If I can't do this, is there a work-around, like having each class contain a pointer to the other class type? Thanks! Here's what I have: File: bar.h #ifndef BAR_H #define BAR_H #include "foo.h" class bar { public: foo getFoo(); protected: foo f; }; #endif File: foo.h #ifndef FOO_H #define FOO_H #include "bar.h" class foo { public: bar getBar(); protected: bar b; }; #endif File:

问题 Given this code sample: complex.h : #ifndef COMPLEX_H #define COMPLEX_H #include <iostream> class Complex { public: Complex(float Real, float Imaginary); float real() const { return m_Real; }; private: friend std::ostream& operator<<(std::ostream& o, const Complex& Cplx); float m_Real; float m_Imaginary; }; std::ostream& operator<<(std::ostream& o, const Complex& Cplx) { return o << Cplx.m_Real << " i" << Cplx.m_Imaginary; } #endif // COMPLEX_H complex.cpp : #include "complex.h" Complex: