Reading a text file - fopen vs. ifstream
开发者_开发问答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";
}
Since this is tagged as C++, I will say ifstream. If it was tagged as C, i'd go with fopen :P
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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