nested structures in C - c

Question

goal: ask user for the number of agencies, create said agencies, and for each agency ask for the number of employees, and create those employees.
part of this will require, I think, nested structure, something like
typedef struct agence agence;
struct agence
{
char nom[20];
int nmbrEmp;
struct employe
{
char mat[20];
int nmbrEnf;
int ANC;
double SB;
double RCNSS;
}
};
is this n the right path, and how do you proceed to create the number of agencies/employees once the users gives you the number required of each.

Answer 1

C unlike C++ cannot have nested types, you will have to declare them separately.
struct employe
{
char mat[20];
int nmbrEnf;
int ANC;
double SB;
double RCNSS;
};
struct agence
{
char nom[20];
int nmbrEmp;
struct employe * employees; // pointer to an array of employees
};
Then use dynamic memory and populate them:
struct agence * agencies;
size_t num_agencies = 100;
agencies = calloc(sizeof(*agencies), num_agencies);
for (/* read egancies somehow */) {
agencies[i].nmbrEmp = number_employees;
agencies[i].employees = calloc(sizeof(agencies[i].employees[0]), number_employees);
// write agencies[i].employees[j] ...
}

Answer 2

Consider this Example :
struct Employee
{
char ename[20];
int ssn;
float salary;
struct date
{
int date;
int month;
int year;
}doj;
}emp1;
Accessing Nested Members :
Accessing Month Field : emp1.doj.month
Accessing day Field : emp1.doj.day
Accessing year Field : emp1.doj.year
Here is the Code pad which will demonstrate the above example
enter link description here

Answer 3

In c, you cannot have unnamed nested structures [otherwise, nested types]. They have to be a named structure. You need to write something like
typedef struct agency
{
char nom[20];
int nmbrEmp;
struct employee
{
char mat[20];
int nmbrEnf;
int ANC;
double SB;
double RCNSS;
} emp [20];
}agency;
However, here you are limited to the static input of a size 20, that means, you cannot have more than 20 employee records. To liberate from this limitation , the best approach is to use a pointer to an employee structure, an in runtime, allocate memory based on the number of the employee given by the user.

Answer 4

Here's an example you might consider. This is a template of what you have to do, you are left with manipulating employees, agencies name and so on. (Note that there's no error checking, which is bad.)
#include <stdio.h>
#include <stdlib.h>
/* TODO: modify members */
typedef struct {
int id;
int salary;
} employee;
/* TODO: modify members */
typedef struct {
char name[20];
employee* emps;
int emps_count;
} agency;
/* return sum of id and salary for first employee from agency */
int dumb_calc(agency ag) {
return ag.emps[0].id + ag.emps[0].salary;
}
int main(void)
{
int num_ag;
int num_emps;
int i, j;
printf("enter num of agencies:\n");
scanf("%d", &num_ag);
agency* agencies = malloc(sizeof(agency) * num_ag);
for (i = 0; i < num_ag; ++i) {
/* TODO: modify single agency name */
sprintf(agencies[i].name, "agency %d", i+1);
printf("enter num of employees for agency %d\n", i+1);
scanf("%d", &num_emps);
agencies[i].emps = malloc(sizeof(employee) * num_emps);
agencies[i].emps_count = num_emps;
for (j = 0; j < num_emps; ++j) {
/* TODO: modify single employee */
agencies[i].emps[j].id = j+1;
agencies[i].emps[j].salary = 1000*(j+1);
}
}
/* TODO: change printing style */
for (i = 0; i < num_ag; ++i) {
printf("agency name: %s\n", agencies[i].name);
printf("num of employees: %d\n", agencies[i].emps_count);
/* result will always be the same */
printf("sum of id and salary for 1st emp: %d\n", dumb_calc(agencies[i]));
}
/* remember to free what you've alloc'd */
for (i = 0; i < num_ag; ++i) {
free(agencies[i].emps);
}
free(agencies);
return 0;
}