End of File in C++

Question

I have a n X 2 matrix stored in a text file as it is. I try to read it in C++

nb_try=0;
fin>>c_tmp>>gamma_tmp;
while (!fin.eof( ))      //if not          


        

Answer 1

If the text file contains this sequence, without quotes, "12345 67890", then #3 will return false, but #4 will return true because there is no whitespace after the last number:

int i;
bool b;

fin >> i;

b = fin.fail();  // 1
b = fin.eof();   // 2

fin >> i;

b = fin.fail();  // 3
b = fin.eof();   // 4

fin >> i;

b = fin.fail();  // 5
b = fin.eof();   // 6

However, if the sequence is "12345 6789 " (note the space after the last number), then #3 and #4 will both return false, but #5 and #6 will return true.

You should check for both, eof() and fail() and if both are true, you have no more data. If fail() is true, but eof() is false, there's a problem with the file.