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File input.

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Join Date: Dec 2004

Posts: 489

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Acidburn

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File input.

Dec 5th, 2005

Hey guys and gals.

I'm struggling yet again to get my file input working. I have a text file containing:

John 19 smith 15 03 1986
Billy 15 Nomate 19 07 1990

...
etc

I'm needing to get a line in at a time but also store the variables in different types.

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include <iostream>
#include <fstream>
#include <cstring>
 
using namespace std;
 
int main()
{
	ifstream infile;
char buffer[25];
char firstname[25];
 
 
infile.open("emp.txt");
 
if (infile.fail())
{
	cerr << "error " <<endl;
	exit(1);
}
char ch;
while((ch = infile.get()) !=EOF && (ch!=' '))
 
 
cout << ch;
 
return 0;
}
#include <iostream>
#include <fstream>
#include <cstring>

using namespace std;

int main()
{
	ifstream infile;
char buffer[25];
char firstname[25];


infile.open("emp.txt");

if (infile.fail())
{
	cerr << "error " <<endl;
	exit(1);
}
char ch;
while((ch = infile.get()) !=EOF && (ch!=' '))


cout << ch;

return 0;
}

I've got this and it prints out "john" which is fair enough. But how do i get it to start doing the '19' and smith part along with the rest.

Since I'll have varibles called

char firstname[20];
char surname[20];
int age;
...etc all numbers need storing differently. (ie in each own int or char varible).

Make sence I hope so.

Thanks,

John

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Join Date: Aug 2005

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Ancient Dragon Ancient Dragon is offline

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Re: File input.

Dec 5th, 2005

you are going about this the hard way. This is a c++ program -- stop using C character arrays :mad:

You don't have to read the bloody file one character at a time. fstream has operators and functions that will read entire words or numbers into your program for you. All you have to do is learn how to use them. For example

Help with Code Tags

C++ Syntax (Toggle Plain Text)

int n;
infile >> n;

That will read an integer directly into the variable.

Help with Code Tags

C++ Syntax (Toggle Plain Text)

std::string last_name, first_name, mi;
infile >> last_name >> first_name >> mi;

or you can put all the above all on one line

Help with Code Tags

C++ Syntax (Toggle Plain Text)

std::string first_name, last_name;
int age;
infile >> first_name >> age >> last_name;

and use infile.is_open() to test that the file was opened ok, infile.fail() may not work as expected.

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Join Date: Dec 2004

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Acidburn

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Re: File input.

Dec 5th, 2005

Hello again, I've created a struct not allowed to create a class, and pop'd in there Char firstname[20];

so the struc is called record;

so i create a 'new' (dynamically) record called (p) and do:

infile >> p->firstname;

...

cout << p->firstname;

However at runtime the program crashes, anyone help us out?

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Acidburn

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Re: File input.

Dec 5th, 2005

disregard pervious post, i fiddled around and got it to work. However I'm struggling to figure out how to get the next line of fields?

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Ancient Dragon Ancient Dragon is offline

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Re: File input.

Dec 5th, 2005

•

Originally Posted by Acidburn

disregard pervious post, i fiddled around and got it to work. However I'm struggling to figure out how to get the next line of fields?

Our crystal ball is out of order today. Guess you'll have to post your new code :p

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Join Date: Dec 2004

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Acidburn

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Re: File input.

Dec 5th, 2005

•

Originally Posted by Ancient Dragon

Our crystal ball is out of order today. Guess you'll have to post your new code :p

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
	ifstream infile;
 
	infile.open("info.txt");
 
	if(infile.is_open())
	{		
		infile >> temp->name;
	}
 
	else
	{
		cerr << "Failure in opening file"<< endl;
		exit (1);
	}	
 
	cout << temp->name;
 
}
	ifstream infile;

	infile.open("info.txt");

	if(infile.is_open())
	{		
		infile >> temp->name;
	}

	else
	{
		cerr << "Failure in opening file"<< endl;
		exit (1);
	}	

	cout << temp->name;

}

since the file contains more than one line how'd do i go through reading 1 line at a time like this?

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Ancient Dragon Ancient Dragon is offline

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Re: File input.

Dec 5th, 2005

you should normally use a loop to read all the lines of a file. For example

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
while( infile >> temp->name )
    cout << temp->name << endl;
while( infile >> temp->name )
    cout << temp->name << endl;

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Acidburn

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Re: File input.

Dec 6th, 2005

•

Originally Posted by Ancient Dragon

you should normally use a loop to read all the lines of a file. For example
Help with Code Tags

C++ Syntax (Toggle Plain Text)
while( infile >> temp->name )
    cout << temp->name << endl;
while( infile >> temp->name ) cout << temp->name << endl;

thats not going to work, I'm putting them into a storage and then calling a function.

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
 
while(infile >> temp->name >> temp->age)		
  {
insert(); // call the function
}
while(infile >> temp->name >> temp->age)		
  {
insert(); // call the function
}

the while loop no longer calls insert... and if im wrong it wont do it for each line?

amd this causes and infinitive loop:

[php]
while(!infile.eof())
{
cout << "********************" << endl;
infile >> temp->name >> temp->age;
frontinsert(); // insert it into the node.
}

[/php]

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Ancient Dragon Ancient Dragon is offline

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Re: File input.

Dec 6th, 2005

•

Originally Posted by Acidburn

thats not going to work, I'm putting them into a storage and then calling a function.
Help with Code Tags

C++ Syntax (Toggle Plain Text)
 
while(infile >> temp->name >> temp->age)		
  {
insert(); // call the function
}
while(infile >> temp->name >> temp->age) { insert(); // call the function }
the while loop no longer calls insert... and if im wrong it wont do it for each line?

you are wrong -- that loop will read each line until end-of-file is reached (assuming each line contains name and age). Call whatever functions you want within that loop. You can pass temp to insert() if insert() needs the information.

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Acidburn

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Re: File input.

#10

Dec 6th, 2005

•

Originally Posted by Ancient Dragon

you are wrong -- that loop will read each line until end-of-file is reached (assuming each line contains name and age). Call whatever functions you want within that loop. You can pass temp to insert() if insert() needs the information.

well it causes and infitite loop