c programming

File: 4) typedef struct { char name[50]; int id; char dept[20]; ; } student; a) Write a function void saveByDept(char *fileName, char * size) that will save the information of all students who belong to by deptName into a text file. The name of the file is given double cgpa; b) Write another function to delete the students of the depar equal to 3 from the file you have created in part (a)