How to read a .dat file in C.

I have created a .dat file (input.dat) which is a 2-dimensional array containing the x and y corordinates of points. Example

1.000, 2.0000
3.000, -1.000
-2.000, 0.000 .........

I want to open this file, read the data and use the data given here to do some calculations and store the result in another output file (output.dat) which will again be a 2-dimensional file.

How to read the data ?

fopen to open the file
fgets in a while loop, to read each line
sscanf to parse each line