There are two relations in this assigment:

Employee {
 int id;
 int age;
 int proj;
 int salary;
 int rating;
 int dept;
} Employee; // Definition of R relation
 

typedef struct Project {
 int id;
 int fund;
 int manager;
 int status;
} Project; // Definition of S relation

We always join R and S by the proj attribute of Employee and id attribute of Project.(Equal Join)

In main.cpp, we create the relation, write them into two heapfiles, and create a Join Specification for each of them.