ramana <ra**********@gmail.comwrote:
I'm wondering if someone could point me to the flaw in the following
code that uses the while(!FP.eof()) condition to read the input data.
This condition is reading the last data point of the file twice.
#include <iostream>
#include <fstream>
using namespace std;
int main(int argc, char **argv)
{
double x;
ifstream FP("test.d");
//while(!FP.eof()){FP >x; cout << x << endl;} // This reads the
last data point of test.d twice
The reason the last data point is "read" twice is this... When the last
data point is read the first time, eof() still false because you haven't
reached the end of the file yet, then it attempts to read another data
point, but none exists, so eof is set to true and x is left unchanged,
so the last data point outputs a second time.
while(FP >x){cout<< x << endl;} // This doesn't.
This one works as follows... The last data point is read, then FP is
true so the data point is printed out, then when it goes to read more,
there isn't any os FP returns false and the loop isn't executed anymore.