fopen is for low-level file operations you may not need.
Perhaps try
data = importdata('stud_ex.txt')
Which will give you a struct with three fields:
data: [7×4 double]
textdata: {7×1 cell}
rowheaders: {7×1 cell}
The row headers are irrelevant, since you don't have headers. But you could use data.data and data.textdata.
Split the data array into student IDs and grades.
