reading from a file and turning it to a matrix

I just started leaning c programming, and i have been doing alright, but now am stuck with a problem, I do not know how to read information from a file in c. the file contains info like;

123456789123456789123456789123456789…and so on. i have to read the file in, and then group the numbers in the file into 7, make them a coulumn matrix and multipy each of the column matrix with another matrix. ive written the code to multiply two matrixs and it works, i just dont know how to group the numbers into groups of 7 and make them a colum matrix like below.

1 1 1

2 2 2

3 3 3

4 4 4

5 5 5

6 6 6

7 7 7

8 8 8

9 9 9

http://bit.ly/mrUCh2