Reading CSV file using C++

[Abhirami_1]

Create a c++ program that reads a CSV file and prints the rows at even positions. For example, if the CSV file has 10 rows, print rows 2, 4,6, 8 and 10

[Dani]

This seems like a homework assignment. What do you have so far? Where are you stuck?

[Husoski]

In a weird way, C++ makes this harder than plain C, provided that you know the maximum line length in advance. (The strtok() function from <string.h> will help split up a C string into comma-separated tokens.) That idea probably won't get a good grade on your C++ assignment, even though it's technically legal & standard to include <cstring> and use the C-style string library.

What I'd suggest is to use std::getline() (the function from <string>, not the getline method of std::cin) to read whole lines into C++ string object, then use the string's .find() member function. In a string named "line", line.find(',') will return the index of the first comma and line.find(',', cpos+1) will find the index of the next comma after some previous comma position "cpos".

Use the .substr() member function to extract the individual values. There are a bunch of options, but the most common use you'll have is to use line.substr(start, stop-start) to extract characters starting at line[start] up to but not including line[stop]. In your program, (start) will be the index of the first character of a comma-separated value, and (stop) will be the index of the comma that end the value.

See docs at: http://www.cplusplus.com/reference/string/string/
or more authoritative (but a bit less readable) docs at: https://en.cppreference.com/w/cpp/string/basic_string

[rproffitt]

Maybe this is easier than it sounds. The CSV lines don't split over a CR/LF (see https://en.wikipedia.org/wiki/Comma-separated_values ) so for this assignment there appears to be no need to parse the CSV content.

Just a simple while loop with a conditional if and print statements.

Psuedo code might be:

open input file.
while not eof input file
    {
    readline()
    if not eof input file
        {
            readline()
            print a line
        }
    }
close input file

[rproffitt]

A, consider the following.

1. "Create a c++ program that reads a CSV file and prints the rows at even positions. For example, if the CSV file has 10 rows, print rows 2, 4,6, 8 and 10"
2. "print the rows in even manner"

Sorry but I can't begin to guess what "print the rows in even manner" means here. Your top post actually doesn't sound hard at all but maybe there's more to the assignment than stated?

[rproffitt]

Please explain what is " print the rows in even manner ".

The top post appears to ask to "print the even rows" and now you ask " print the rows in even manner " so you'll have to explain in detail how this differs.