C++ reading in a file, ignoring commas and outputting data to the screen

Question

I have a file in the format: FirstName,MiddleName,LastName,Major,City,State,GPA

I'm trying to read in the file and output the data without the commas to the screen. This is what I have so far, but it only outputs the GPA's:

#include <fstream>
#include <iostream>
#include <string>
#include <sstream>

using namespace std;
int main(){
    string fileline;
    string word;
    ifstream studentData;
    studentData.open("studentData.csv");
    while(studentData){
        getline(studentData,fileline);
        istringstream ss(fileline);
        while(getline(ss, word,','));{
            cout << word << '\n';

        }

    }
    return(0);
}

Use `getline` in `while`. You did it for the second (although with a stay `;`) but not the first loop. — Neil Kirk, Nov 06 '15 at 00:48

score 1 · Answer 1 · answered Nov 06 '15 at 00:42

1

I think the problem is this line:

while(getline(ss, word,','));{

Try removing the semicolon. This would be the right way:

while(getline(ss, word,',')){

The semicolon makes the loop do nothing until it reads the last word (which I'm guessing is the GPA), which you then print.

Let us know if that works!

answered Nov 06 '15 at 00:42

Guilherme Sena

117
7

That did the trick. Currently it prints out each word on its own line. I'm trying to figure out how to only print to a new line once i reach the end of a line, so it would print 7 words then start a new line. Any tips? – Jordan C Nov 06 '15 at 00:45
Yes. It's printing a new line because of the \n at the end of cout. To print with spaces you can do something like this: while(getline(ss, word,',')){ cout << word << " "; //Print a space instead of a new line } cout << "\n"; //And only then print the end of the line – Guilherme Sena Nov 06 '15 at 00:46
I want to output the data in the same form that it starts in, just without commas. If i do ' ' instead of '\n' it will put every word it finds next to one another. (I should have mentioned that the input file has around 27 lines). so I want to print out 7 words then new line rinse and repeat – Jordan C Nov 06 '15 at 00:51

Jerry Coffin · Answer 2 · 2015-11-06T00:50:41.510

If you just want to copy without commas, why not just copy without commas?

ifstream studentData("StudentData.csv");

studentData >> noskipws;

std::remove_copy(std::istream_iterator<char>(studentData),
                 std::istream_iterator<char>(), 
                 std::ostream_iterator(std::cout)
                 ',');

OTOH, if your input doesn't have anything separating the fields except the commas, this will produce output with them all run together. You might prefer to write out a space character between fields instead:

std::transform(std::istream_iterator<char>(studentData),
               std::istream_iterator<char>(),
               std::ostream_iterator<char>(std::cout),
               [](char ch) { return ch == ',' ? ' ' : ch; });

This way you'll still have something to help keep track of where one field ends and the next starts. Of course, if you prefer, say, a tab rather than a space, you can change the space to a tab.

score 0 · Answer 3 · answered Nov 06 '15 at 00:48

The semicolon in while(getline(ss, word, ','); shouldn't be there. That said, stringstreams are slow, I'd prefer to do this as follows.

while(std::getline(studentData, fileline)) {
    std::erase(std::remove(fileline.begin(), fileline.end(), ','), fileline.end());
    std::cout << fileline << '\n';
}

C++ reading in a file, ignoring commas and outputting data to the screen

3 Answers3