why it does this? 1

[rick05]

hi guys...

I have a little trouble, I´m reading from a file with ifstram, since I want to review the format of this file...

however when I use file.oef() in my loop, my program read the last data two times! :-(( do U know what happens?

my code is:

¦float val1;
¦int fin;
¦
¦ifstream hoyos("hoyo"
¦
¦if (!hoyos.fail())
¦ {
¦
¦ while (!hoyos.eof())
¦ {
¦ cout << &quot;si se pudo abrir el archivo!\n&quot;;
¦ hoyos >> val1;
¦ cout << &quot;valor de val1: &quot; << val1 << &quot;\n&quot;;
¦ getch();
¦ };
¦

my trouble is if my file is :

1 2 3 4
5 6 7 8

my program lists:

1
2
3
4
5
6
7
8
8

two times the last one!

why??!!!

I hope U can help me... please...

rick

 

[Zyrenthian]

just change your while to this

while(!hoyos.eof() && hoyos.peek() != EOF)

eof is funky. I think it was meant to be used as a condition in a do-while loop.


Matt

 

[rick05]

hi Matt...

well, I tried your advise, however is the same :-(

I tried it with a do-while loop, and a while loop and did the same...

:-((

thx anyway.

 

[Zyrenthian]

Well... then my next assumption is this:

You dont reach the end of the file when reading in 8 and then when you try to read into val again nothing happens because there is no numerical value and it reaches eof. You may need to do a getline and use atoi. Im gonna cut and paste your code into a program and see what happens.

Matt

 

[Zyrenthian]

Here ya go

void main()
{


float val1;
int fin;

ifstream hoyos(&quot;hoyo.txt&quot;

if (!hoyos.fail())
{

while (!hoyos.eof() && hoyos.peek()!= EOF)
{
cout << &quot;si se pudo abrir el archivo!\n&quot;;
hoyos >> val1;
cout << &quot;valor de val1: &quot; << val1 << &quot;\n&quot;;
hoyos.get();
}
}


}//end of main function

Matt

 

[smaniraja]

Your problem is not in findig the end of file. you are printing the value of the variable val1 after the end of file is reached. After the end of file the variable val1 will have the previous value and that is printed again, after the print ( cout ) only the you are checking the end of file.



¦
¦ while (!hoyos.eof()) // Here you are checking the end of file without reading anything from the file. You have to check this after the read operation only. Change this to an infinite loop like while(1)
¦ {
¦ cout << &quot;si se pudo abrir el archivo!\n&quot;;
¦ hoyos >> val1;
// end of file may will come. At that time val1 will have the previous value.

// put a if statement before the cout

if (hoyos.eof()) break;

¦ cout << &quot;valor de val1: &quot; << val1 << &quot;\n&quot;;

// that previou value will be printed (in the end of file case)
¦ getch();
¦ };
¦


Maniraja S