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Hi i currently wrote a program but I'm having problems with reading the file. It seems to have read the last line twice, as a result, producing the same results twice.

I had put the getline() function to read the first line, in order to store the string for the variable G. The rest, I had stored it in a vector of the class object.

basically the file is opened and it performs this loop

file.open("bodies1.txt");
getline(file, G1);
....


while(!file.eof)
{
  file >> body;
  bodies.push_back(body);
}

this is what the text file look like (this is just a sample. not the actual thing)

0.02932
Sun 32 42 53 2 2
Moon 49 32 4 2 1
Jupiter 32 53 2 3 2

I really was wondering why it read the last line twice. Any suggestions?

user2188311
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    @JesseGood I agree that the EOF is the problem, I'm not sure that this question is a duplicate of that question however. That answer will solve their problem. – AlexLordThorsen Apr 30 '13 at 20:23
  • @Rawrgulmuffins: Problems related to the C++ anti-pattern `while(!file.eof)` are very common. Check out how many duplicates are linked to that question. – Jesse Good Apr 30 '13 at 20:34

1 Answers1

1
while(!file.eof())
{
  file >> body;
  bodies.push_back(body);
}

After reading the last object in to body, eof is the next character. Then 

file >> body;

tries to read it and fails. So whatever was in body before is still there and will be pushed in to the vector.

instead you should read like

while(file >> body)
{
  bodies.push_back(body);
}

This way your while stops as soon as you encounter eof() and you will not do an extra push in to the vector.

stardust
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  • ok that makes sense. It's weird how it reads eof? never knew it was a character – user2188311 Apr 30 '13 at 20:28
  • @user2188311 No it is not really about eof(). It is about when it gets read. In the first case it is read in the loop body. So even if you hit eof the rest of the loop still gets executed. Think about it :) – stardust Apr 30 '13 at 20:30