C++ - 不是类或命名空间错误

Question

我是 C++ 的新手，当我尝试调用 create_event_file() 函数时，出现以下错误“fw”不是主文件中的类或命名空间。

这是我的代码。

#ifndef FILE_WRITER_H
#define FILE_WRITER_H
#include <string>
using namespace std;

class File_Writer{

private:
int test;

public:
File_Writer() { }

void create_event_file(void);
void write(const string file_name, string data);
};

#endif // FILE_WRITER_H

cpp文件

#include "file_writer.h"
#include <iostream>
#include <fstream>
using namespace std;

File_Writer::File_Writer(void){
cout << "Object of File_Writer is created" << endl;
}

void File_Writer::create_event_file(void){

ofstream outputFile;

outputFile.open("event.txt");

string data;
cout << "Enter event title : " << endl;
getline(cin,data);
outputFile << textToSave;

cout << "Enter event date : " << endl;
getline(cin,data);
outputFile << textToSave;

cout << "Enter event start time : " << endl;
getline(cin,data);
outputFile << textToSave;

outputFile.close();
}

void File_Writer::write(const string file_name, string data){

ofstream outputFile;

outputFile.open("all.txt");

outputFile << data;

outputFile.close();
}

和主文件

#include <iostream>
#include "file_writer.h"
using namespace std;


int main(){

string input;
File_Writer fw;

cout << "Welcome to the event creation program!\n" << endl;
cout << "---------------------------" << endl;
cout << "| event - To create event file   |" << endl;
cout << "| entrants - To create entrants file |" << endl;
cout << "| coursess - To create courses file |" << endl;
cout << "---------------------------\n" << endl;

getline(cin,input);

if(input == "event")
    fw::create_event_file();


}

提前致谢

Answer 1

替换它，这意味着 fw 是类或命名空间的名称:

 fw::create_event_file();
// ^^ This is a "scope opearator"

有了这个，这意味着 fw 是一个变量:

 fw.create_event_file();
// ^ This is a "member access opearator"