how can I Use fscanf() inside a loop to read each line in C language?

also how can I take the values from the file and add them together for example if the file contents are

2

4

6

I want to read the first line and add 2 then the second one and add 4 and then the third and 6 and finally return the total 12 and stop reading.

I do not want to store the values in an array so I want to be able to deal with the data while I am reading each line.