为什么 C++ 中的 getline() 不起作用？(没有匹配的函数调用'getline(std::ofstream&, std::string&)'
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Why is getline() in C++ not working? (no matching function for call to 'getline(std::ofstream&, std::string&)'
提问by JVE999
I'm trying to read from a file, but C++ is not wanting to run getline().
我正在尝试从文件中读取，但 C++ 不想运行getline().
I get this error:
我收到此错误：
C:\main.cpp:18: error: no matching function for call to 'getline(std::ofstream&, std::string&)'
std::getline (file,line);
^
This is the code:
这是代码：
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <fstream>
#include <string>
using namespace std;
int main(){
string line;
std::ofstream file;
file.open("test.txt");
if (file.is_open())
{
while ( file.good() )
{
getline (file,line);
cout << line << endl;
}
file.close();
}
}
回答by 0x499602D2
std::getlineis designed for use with input stream classes (std::basic_istream) so you should be using the std::ifstreamclass:
std::getline设计用于与输入流类 ( std::basic_istream) 一起使用，因此您应该使用std::ifstream该类：
std::ifstream file("test.txt");
Moreover, using while (file.good())as a condition for input in a loop is generally bad practice. Try this instead:
此外，while (file.good())在循环中用作输入的条件通常是不好的做法。试试这个：
while ( std::getline(file, line) )
{
std::cout << line << std::endl;
}
回答by Suvarna Pattayil
std::getlinereads characters from an input streamand places them into a string. In your case your 1st argument to getlineis of type ofstream. You must use ifstream
std::getline从输入流中读取字符并将它们放入字符串中。在您的情况下，您的第一个参数getline的类型为ofstream。你必须使用ifstream
std::ifstream file;
