Read adjacency list of digraph from a text file in C++

Question

I have a text file which has some number of integers in each line. Example:

1 2 4
3 
0 4

2 3

Here 1st line means that the 1st node is connected to nodes numbered 1, 2 and 5. Blank line means 4th node isn't connected to any node.

This gives me a directed graph. This SO question might have been helpful but it assumes each line to have 2 integers, whereas in this case it can have any number of integers from 0 to N-1(N is no. of nodes).

I just want to know how to read this text file. If I had two integers per line, I could have done infile >> a >> b. How to know that " " or end of line has occured. I am not asking for code that makes directed graph.

Answer 1

The accepted answer from the linked question already shows you how to read line by line, which you need to do for your code and the first part shows a loop how to read all numbers from your line (istringstream). Because you don't have a fixed number of entries, you might want to store them in a std::vector.