CODEWITHSUNDEEP
c++fileinput
LGdeveloper
LGdeveloper

Reputation: 37

File based input to define graph variables

I am currently trying to create a program in c++ that will allow a user to fill in a text file to define variables for a graph, these variables define the distance between nodes in the graph. The format is as follows:

int numberOfNodes
      //node 0,   node 1 ,   node 2
float distance1, distance2, distance3 //node 0
float distance1, distance2, distance3 //node 1
float distance1, distance2, distance3 //node 2

(number of nodes being 3) which is why there is a 3x3 grid, which would specify the distance between each node.

for contect: filedata.txt

3
0 1 2
1 0 3
2 3 0

I understand that to use file input you use fstream, along with ifstream to select the file to open. What I dont understand is how to put this data into context.

How do i tell c++ that the first line will always be how many nodes there are in the list, then how would I tell c++ that anything under that first line is the data I want to fill into their own lists?

while (infile >> size)
{
     cout <<"Total number of Verticies in Graph = "<<  size << endl; 
}

Upvotes: 0

Views: 46

Answers (1)

πάντα ῥεῖ
πάντα ῥεῖ

Reputation: 1

With input like that:

3

First read the number of rows, and go into a for loop:

infile >> numrows;
for(int row = 0; i < numrows; ++i) {
}

The subsequent input can be read as 

0 1 2
1 0 3
2 3 0

infile >> distance1 >> distance2 >> distance3;

inside of the loop.

Upvotes: 1

Related Questions