C++ 将程序拆分为头文件和主文件

我一直在尝试将我的程序分为头文件和主文件，但不太清楚头文件到底如何处理这个文件。任何试图理解这一点的帮助都将不胜感激

#include <iostream>
#include <fstream>
#include <string>
#include <set>


void comparing(std::ifstream& fileIn, std::ifstream& keywords, std::ofstream& outFile)
{
    std::string str;
    std::string word;
    std::set<std::string> keywordsSet;
        int check = 0;

        while (keywords >> word) {
        keywordsSet.insert(word);
        }

    while(fileIn >> str){

        if(str == "<p>") {
            check++;
        }


        if((check > 1 && str == "<p>") || (check == 1 && str == "</body>"))
        {
            outFile << "</p>";
            check--;
        }



    if(keywordsSet.find(str) != keywordsSet.end()) {

        outFile << "<i>" << str << "</i>" << " ";
        }

        else{
        outFile << str << " ";
        }           
    }   

}
int main(int argc, char* argv[])
{

std::ifstream fileIn;
fileIn.open (argv[1]);

std::ifstream keywords;
keywords.open (argv[2]);

std::ofstream outFile;
outFile.open(argv[3]);

    comparing(fileIn, keywords, outFile);

fileIn.close();
keywords.close();
outFile.close();

return 0;
}

#包括
#包括
#包括
#包括
无效比较（std:：ifstream和fileIn，std:：ifstream和关键字，std:：ofstream和outFile）
{
std：：字符串str；
字符串字；
std:：set关键字set；
整数检查=0；
while（关键字>>word）{
关键字设置。插入（word）；
}
while（fileIn>>str）{
如果（str==“”）{
check++；
}
如果（（check>1&&str==“”）| |（check==1&&str==”）
{
outFile通常将类和函数声明放在头文件中，然后将定义和实现放在
.cpp
文件中。
在代码中声明一个函数：
比较
。通常将所有声明放在头文件中（MSVC++使用了<代码> .H/COD>后缀，但我更喜欢 .HPP C++标题），以及在> CPP文件
中的实现。
您的标题（
comparing.hpp
，或类似的内容）如下所示：

// Prevents redefinitions when including the same header multiple times
#pragma once

// Does the same thing, just to make sure 
// (some compilers don't support #pragma once)
#ifndef COMPARING_HPP
#define COMPARING_HPP

#include <fstream>

void comparing(std::ifstream&, std::ifstream&, std::ofstream&); // Function prototype

#endif

#include "comparing.hpp"
// Note the quotation marks instead of greater than, less than signs
// This is because the header is not in the standard include path,
// but rather in your project include path.

// Implementation, belongs in cpp file
void comparing(std::ifstream& fileIn, std::ifstream& keywords, std::ofstream& outFile)
{
    std::string str;
    std::string word;
    std::set<std::string> keywordsSet;
        int check = 0;

        while (keywords >> word) {
        keywordsSet.insert(word);
        }

    while(fileIn >> str){

        if(str == "<p>") {
            check++;
        }


        if((check > 1 && str == "<p>") || (check == 1 && str == "</body>"))
        {
            outFile << "</p>";
            check--;
        }



    if(keywordsSet.find(str) != keywordsSet.end()) {

        outFile << "<i>" << str << "</i>" << " ";
        }

        else{
        outFile << str << " ";
        }           
    }   

}

#include "comparing.hpp"

int main(int argc, char* argv[])
{

std::ifstream fileIn;
fileIn.open (argv[1]);

std::ifstream keywords;
keywords.open (argv[2]);

std::ofstream outFile;
outFile.open(argv[3]);

    comparing(fileIn, keywords, outFile);

fileIn.close();
keywords.close();
outFile.close();

return 0;
}

然后，您可以在任何
.cpp
中使用
compare
功能，只要包含标题即可。因此，您的
main.cpp
*文件如下所示：

// Prevents redefinitions when including the same header multiple times
#pragma once

// Does the same thing, just to make sure 
// (some compilers don't support #pragma once)
#ifndef COMPARING_HPP
#define COMPARING_HPP

#include <fstream>

void comparing(std::ifstream&, std::ifstream&, std::ofstream&); // Function prototype

#endif

#include "comparing.hpp"
// Note the quotation marks instead of greater than, less than signs
// This is because the header is not in the standard include path,
// but rather in your project include path.

// Implementation, belongs in cpp file
void comparing(std::ifstream& fileIn, std::ifstream& keywords, std::ofstream& outFile)
{
    std::string str;
    std::string word;
    std::set<std::string> keywordsSet;
        int check = 0;

        while (keywords >> word) {
        keywordsSet.insert(word);
        }

    while(fileIn >> str){

        if(str == "<p>") {
            check++;
        }


        if((check > 1 && str == "<p>") || (check == 1 && str == "</body>"))
        {
            outFile << "</p>";
            check--;
        }



    if(keywordsSet.find(str) != keywordsSet.end()) {

        outFile << "<i>" << str << "</i>" << " ";
        }

        else{
        outFile << str << " ";
        }           
    }   

}

#include "comparing.hpp"

int main(int argc, char* argv[])
{

std::ifstream fileIn;
fileIn.open (argv[1]);

std::ifstream keywords;
keywords.open (argv[2]);

std::ofstream outFile;
outFile.open(argv[3]);

    comparing(fileIn, keywords, outFile);

fileIn.close();
keywords.close();
outFile.close();

return 0;
}


<>代码>主体.CPP< /Cord>文件不需要标题；为什么你需要在代码中别处调用<代码>主<代码>？< /P>你应该投资一本好的C++书籍。