读取文本文件 - fopen 与 ifstream

发布于 2024-11-16 08:58:08 字数 680 浏览 1 评论 0原文

谷歌搜索文件输入我发现了两种从文件输入文本的方法 - fopen 和 ifstream。下面是两个片段。我有一个文本文件，其中包含一行，其中包含一个我需要读入的整数。我应该使用 fopen 还是 ifstream？

片段 1 - FOPEN

FILE * pFile = fopen ("myfile.txt" , "r");
char mystring [100];
if (pFile == NULL) 
{
    perror ("Error opening file");
}
else 
{
    fgets (mystring , 100 , pFile);
    puts (mystring);
    fclose (pFile);
}

片段 2 - IFSTREAM

string line;
ifstream myfile ("example.txt");
if (myfile.is_open())
{
    while ( myfile.good() )
    {
        getline (myfile,line);
        cout << line << endl;
    }
    myfile.close();
}
else 
{  
    cout << "Unable to open file"; 
}

原文

Googling file input I found two ways to input text from a file - fopen and ifstream. Below are the two snippets. I have a text file consisting of one line with an integer I need to read in. Should I use fopen or ifstream?

SNIPPET 1 - FOPEN

FILE * pFile = fopen ("myfile.txt" , "r");
char mystring [100];
if (pFile == NULL) 
{
    perror ("Error opening file");
}
else 
{
    fgets (mystring , 100 , pFile);
    puts (mystring);
    fclose (pFile);
}

SNIPPET 2 - IFSTREAM

string line;
ifstream myfile ("example.txt");
if (myfile.is_open())
{
    while ( myfile.good() )
    {
        getline (myfile,line);
        cout << line << endl;
    }
    myfile.close();
}
else 
{  
    cout << "Unable to open file"; 
}

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给我一枪 2024-11-23 08:58:08

因为它被标记为 C++，所以我会说 ifstream。如果它被标记为 C，我会选择 fopen :P

回复收藏 0 原文

谎言 2024-11-23 08:58:08

我更喜欢 ifstream，因为它比 fopen 更加模块化。假设您希望从流中读取的代码也从字符串流或任何其他 istream 中读取。您可以这样写：

void file_reader()
{ 
    string line;
    ifstream myfile ("example.txt");
    if (myfile.is_open())
    {
        while (myfile.good())
        {
          stream_reader(myfile);
        }
        myfile.close();
    }
    else 
    {  
        cout << "Unable to open file"; 
    }
}

void stream_reader(istream& stream)
{
    getline (stream,line);
    cout << line << endl;
}

现在您可以在不使用真实文件的情况下测试stream_reader，或者使用它从其他输入类型读取。这对于 fopen 来说要困难得多。

I would prefer ifstream because it is a bit more modular than fopen. Suppose you want the code that reads from the stream to also read from a string stream, or from any other istream. You could write it like this:

void file_reader()
{ 
    string line;
    ifstream myfile ("example.txt");
    if (myfile.is_open())
    {
        while (myfile.good())
        {
          stream_reader(myfile);
        }
        myfile.close();
    }
    else 
    {  
        cout << "Unable to open file"; 
    }
}

void stream_reader(istream& stream)
{
    getline (stream,line);
    cout << line << endl;
}

Now you can test stream_reader without using a real file, or use it to read from other input types. This is much more difficult with fopen.

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