Solved

read data from file

Posted on 2002-03-16
3
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Last Modified: 2010-04-01
Hi experts,

I have problem in reading data correctly from my file file.

The format is as follows:

Company ABC
3  A1
5  B1
6  C1
0
Company XYZ
6  A1
8  B1
5  C1
0
Company RTG
1  A1
4  B1
3  C1
0

My code as follows:

ifstream inFile;
inFile.open("input.txt");

inFile.getline(company, 40);
cout <<company<<endl;
inFile >>cost>>product;

while(!inFile.eof()){
     //How should I detect the '0' char?
        //I need to manipulate the three data
        //(company,cost,product) for the first
        //record before I move to the another
        //record by detecting the '0' char.
}

Pls include explanation with your solution.Thanks!
p.s Any C++ tutorial for beginner like me?
0
Comment
Question by:Celia
3 Comments
 
LVL 16

Accepted Solution

by:
Peter Kwan earned 50 total points
ID: 6870846
Assume the variable cost is declared as an integer (i.e. int cost;).

You need to declare a temporary variable, say temp, of type char (i.e. char temp;).

Here is a sample code of the while loop:

====================================================
  while (!inFile.eof()) {
    inFile >> cost;

    if (inFile.eof()) // detecting the end of file to avoid repeating at the end
      break;

    if (cost==0) { // end of record
      inFile.get(temp); // why? see explanation below.
      inFile.getline(company, 40);
    }
    else {
      inFile >> product;
    }
  }
===================================================
The reason for using a get statement is because we want to skip the "end of line" character after 0. If not using this, then it will falls into infinity loop, since getline does not skip the "end of line" character.
0
 
LVL 12

Expert Comment

by:lexxwern
ID: 6875876
or else you use 0 as the seperating character.
use \n instead. cuse the u can use the << and >> operators with much ease.

Let this be the sample Data
Company ABC
3  A1\n
5  B1\n
6  C1\n
\n
Company XYZ
6  A1\n
8  B1\n
5  C1\n
\n
Company RTG
1  A1\n
4  B1\n
3  C1\n
\n
sample code


struct YOUROBJ company[10];
fstream read("YOURFILE");int c=0;
for(int i=0; i<10;i++)
{
  while(read)
  {
    char temp[1000];
    read>>temp;
    if(!temp) break;
    strcpy(company[i].SUBOBJECT[c++],temp);
  }
}

this is just an example on how to go about using the \n and << >> operators to your advantage. Other solutions are also present.


lhn.
0
 
LVL 11

Expert Comment

by:griessh
ID: 6955389
Dear Celia

I think you forgot this question. I will ask Community Support to close it unless you finalize it within 7 days. You can always request to keep this question open. But remember, experts can only help you if you provide feedback to their questions.
Unless there is objection or further activity,  I will suggest to accept

     "pkwan"

comment(s) as an answer.

If you think your question was not answered at all, you can post a request in Community support (please include this link) to refund your points. The link to the Community Support area is: http://www.experts-exchange.com/commspt/

PLEASE DO NOT ACCEPT THIS COMMENT AS AN ANSWER!
======
Werner
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