Quiz 2

Problem Statement:

Your friend Raphael is again facing another predicament. His elementary school wanted him to submit his class roster as a .txt file, which would contain the enrollment numbers and the names of each of the students. Initially, he had put down the data in the format of <enrollment no.> <first_name> <last_name&rt;. However, the school, being in Japan, writes names in reverse order, ie they write the names in the format <last name> <first name>.

Raphael does not have the time to rewrite the rosters for all his students. He wants your help to change the formatting to what the school wants: <enrollment no.> <last_name> <first_name>.

Write a program in C++ that reads in a file named records.txt, which contains the records of the students in the first format, and fixes the records in the second format and churns out a file named records_fixed.txt.

Sample input (records.txt)

Sample output (records_fixed.txt)

Solution

This is a simple exercise in file I/O. Note that each line of records.txt consists of an int roll, a string firstname, and a string lastname. You should just read in these things in order and write to records_fixed.txt in the fixed order.

#include <iostream>
#include <fstream>
using namespace std;

int main()
{
	int roll;
	string firstname, lastname;
	ifstream fin("records.txt",ios::in);
	ofstream fout("records_fixed.txt",ios::out);
	if(!fin.is_open() || !fout.is_open())  // If there was some error opening these files, abort.
	{
		cout<<"Error opening records.txt or records_fixed.txt...";
		return 1;
	}
 	// Read in the records via fin and write them out via fout!
	while(!fin.eof())
	{
		fin>>roll>>firstname>>lastname;
		fout<<roll<<" "<<lastname<<" "<<firstname<<endl;
	}
	// Close the file streams after finishing your work.
	fin.close();
	fout.close();
	cout<<"Fixing records complete.\n";
	return 0;
}