How to use stringstream to separate comma separated strings [duplicate]

Question

I've got the following code:

std::string str = "abc def,ghi";
std::stringstream ss(str);

string token;

while (ss >> token)
{
    printf("%s\n", token.c_str());
}

The output is:

abc
def,ghi

So the stringstream::>> operator can separate strings by space but not by comma. Is there anyway to modify the above code so that I can get the following result?

input: "abc,def,ghi"

output:
abc
def
ghi

Undercroft

Splitting a string in C++ contains everything a human should know about splittin strings in C++ – Executive

Second answer in the duplicate target also answers this question: https://mcmap.net/q/40394/-how-do-i-iterate-over-the-words-of-a-string – Bismuth

Answer 1

#include <iostream>
#include <sstream>

std::string input = "abc,def,ghi";
std::istringstream ss(input);
std::string token;

while(std::getline(ss, token, ',')) {
    std::cout << token << '\n';
}

abc
def
ghi

Trematode

Why do you guys always use std:: and full namespaces instead of using namespace? Is there specific reasoning for this? I just always find it as a very noisy and had-to-read syntax. – Idiocy

@DmitryGusarov It's a habit and a good practice. It doesn't matter in short examples, but using namespace std; is bad in real code. More here. – Trematode

ah, so it sounds like the problem caused by c++ ability to have a method outside of a class. And probably this is why it never lead to problem in C# / Java. But is it a good practice to have a method outside of a class? Modern languages like Kotlin don't even allow static methods. – Idiocy

In Kotlin, you can declare functions inside companion object inside classes which are basically static methods. – Misfeasance

This is short and readable which is great, but is this the fastest way to do it in c++? – Aviv

How do you adapt this answer to skipping white spaces e.g., if std::string input = "abc, def, ghi"; I want to get rid of the white spaces when parsing by commas with getline. – Convolve

Answer 2

#include <iostream>
#include <string>
#include <sstream>
using namespace std;
int main()
{
    std::string input = "abc,def,   ghi";
    std::istringstream ss(input);
    std::string token;
    size_t pos=-1;
    while(ss>>token) {
      while ((pos=token.rfind(',')) != std::string::npos) {
        token.erase(pos, 1);
      }
      std::cout << token << '\n';
    }
}

Upperclassman

This code isn't correct, it generates abcdef \n ghi as output. – Radial