Question

c++

How do I get it before a particular string when I use <ifstream>?

For example, when it's 'Apple: fruit', I only want to get the previous ':' text (Apple).

And then I want to move on to the next row.

How can i do?

Answer 1

Thanks for the question, For your requirement , you need to use getline function

I have demonstrated below as how to do it using a very simple file. Comments are included so that you can understand and apply on your own.

Refer the screenshot of the file and the output. I think this is what you were looking for.

Do let me know in case you need any further help.

=========================================================================

#include<iostream>

#include<fstream>

using namespace std;

int main(){

               

               

                ifstream infile("D:\\veg.txt");

               

                string name,junk;

               

                // use getline to read upto a particular character in a line without reading that particular character ( here it is : )

                // takes 3 arguments, stream, string variable and delimitting character

                // reading stops just before the ':' character

                // string before the character ':' get stored in the variable name

                while(getline(infile,name,':')){

                                cout<<name<<endl;

                                // read the left over to a string variable, with delimiting character as new line character

                                getline(infile,junk,'\n');

                                // move to the next row

                               

                }

                infile.close();

}