CODEWITHSUNDEEP
c++stringfstream
J4X
J4X

Reputation: 119

Extract Information from colon seperated .txt file, C++

guys. I'm writing this small test program to read the text file from "EXAMPLE.txt" into my main program. At the output, I put "*" to displayed the data during the output is the data that I want to extract it out and locate into an array. Let say, in this test program the data that I wanted to extract is "JY9757AC", "AZ9107AC","GY9Z970C". But after that, I have did a try run and I faced this problem when comes to the output.

EXAMPLE.txt

ABC:JY9757AC
HDMI:AZ9107AC
SNOC:GY9Z970C

MAIN.CPP

main()
{
    string output;
    ifstream readExample;
    readExample.open("EXAMPLE.txt");  

    while(readExample.eof())
    {
        getline(readExample,output,':');
        cout << "* " << output <<endl; 
    }
}

OUTPUT

* ABC       //while loop output the "ABC", which is the data that I don't want.
* JY9757AC
HDMI        //it work's well, as what I expected and so and the SNOC below
* AZ9107AC
SNOC
* GY9Z970C

I have no any idea why is the "* ABC" is shown on the output, is there anything wrong with my logic. or I missed out something inside the while loop? Thank You in advance for helping to solve my code!

Upvotes: 0

Views: 432

Answers (3)

robbannn
robbannn

Reputation: 5013

Output stores the first extraction from Example.txt and prints it followed by *. In the first iteration output = "ABC"; in the second iteration output = "JY9757AC";. I have added a getline() in the while loop that reads the unwanted part of the line. I also added a string[] to store the extracted values in.

#include <fstream>
#include <string>


using namespace std;

int main()
{
    string output, notWanted, stringArray[3];
    int i = 0;
    ifstream readExample;
    readExample.open("EXAMPLE.txt");

    while (!readExample.eof())
    {
        getline(readExample, notWanted, ':');
        getline(readExample, output);
        cout << "* " << output << endl;
        stringArray[i++] = output;
    }
    cin.get();

    return 0;
}

Upvotes: 0

GHugo
GHugo

Reputation: 2654

The delim parameter for getline replaces the default delimiter for new line which is "\n". What you are currently getting as a "line" is:

ABC
JY9757AC\nHDMI
AZ9107AC\nSNOC
GY9Z970C

What you can do is more something like this (if your output like GY9Z970C) is fixed-size:

ssize_t len = getline(readExample,output,':');
cout << "* " << (char*)(output + (len - 8)) <<endl;

Upvotes: 1

Mine
Mine

Reputation: 4241

First, I assume the while loop is while(!readExample.eof()), otherwise there should be no output at all.

Second, to your question, the first getline(readExample,output,':'); read "ABC" into the output, so at the next line it outputs * ABC, which is exactly what you got. No surprise.

Upvotes: 0

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