C/C++ :: Display Average GPA Of Some Students In A File

I have learnt about string class, file I/O and pointers. Now I am asked to write a program that includes the above topics, basically testing the ability to use dynamic arrays.

I've got 2 documents, namely "Students.txt" and "EnrollRecords.txt". "Students.txt" includes 40 students' info, which are university ID, programme names and their names. These 40 students are all BEng but from different departments.

E.g. 20141129 BEng(Civil) Tom Jerry

"EnrollRecords.txt" includes 166 data, which are course codes, university ID, respective scores in the test and GPA. In this document, the same student can have several scores of different courses' tests. So their uids repeat in it. And this document only contains the data of the Department of Computer Science. So students exist in the "Students.txt" may not exist in this document.

So my task is that the user enter a name (e.g. John), then the programme will know to find John and his uid, and get all the GPA of the courses that he has taken to calculate the average GPA.

E.g. 20147777 BEng(CompSc) John David //this is a John we are looking for in the "Students.txt"

//line 15 COMP1220 20147777 90 4 //so we find 3 courses in "ErollRecords.txt" that John has taken
//line 50 COMP1500 20147777 85 3.3
//line 88 ENGG2012 2014777 70 2.3

The programme should display :

20147777 3.2

To able to do anything for this task, I am asked to define 4 struct types:

struct Student {
int uid;
string programme;
string name;

[Code] ....

So now I am going to write a function queryD(Database d, string searchName) and any necessary functions in it. I am able to do the search part,

void queryD(Database d, string searchName) {
for (int i = 0; i < d.numberOfStudents; i++) {
if (d.students[i].name.substr(0, searchName.length()) == searchName) {
match_uid(d);

[Code] ....

But I struggle in how to match the uid in "Students.txt" and "EnrollRecords.txt" . Because there are repeated data for the same student in "ErollRecords.txt". So how am I gonna be able to match the uid and do the calculation? I get stuck in the for loop part...