malloc array of struct inside of struct - c

Question

I have project in school where in need to make a struct of AirportManager which holds the amount of airports and an array of Airport (another struct). I started writing the code but I having trouble with the malloc of the array of airports.
I attahced to code I write so far, the problem I have is that the values dont saved in the airportArray in the AirportManager.
//AirportManger Struct
typedef struct {
Airport* airportArray;
int airportAmount;
}AirportManager;
void initAirportManager(AirportManager* airportManager)
{
airportManager->airportAmount = 0;
airportManager->airportArray = (AirportManager*)malloc(0);
}
void addAirport(AirportManager* airportManager)
{
Airport airport;
printf("Enter Airport Name: ");
scanf("%s", airport.airportName);
printf("Enter Airport Address: ");
scanf("%s", airport.airportAddress);
airportManager->airportAmount++;
airportManager->airportArray = (Airport*)realloc(airportManager->airportArray, airportManager->airportAmount * sizeof(Airport));
airportManager->airportArray = airport;
}
//Airport Struct
typedef struct {
char airportName[MAX];
char airportAddress[MAX];
}Airport;
//Main
AirportManager airportManager;
initAirportManager(airportManager);
addAirport(&airportManager);

Answer 1

The code has some issues. We shouln't:
allocate zero bytes with malloc(0)
assign twice to airportManager->airportArray
use scanf
Here is the code modified. It uses malloc and realloc better, and fgets instead of scanf.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define SIZ 512
typedef struct {
char airportName[SIZ];
char airportAddress[SIZ];
} Airport;
typedef struct {
Airport* airportArray;
int airportAmount;
} AirportManager;
// Call first on AirportManager
void initAirportManager(AirportManager* airportManager)
{
airportManager->airportAmount = 0;
airportManager->airportArray = NULL;
}
// Call last on AirportManager
void finalAirportManager(AirportManager* airportManager)
{
airportManager->airportAmount = 0;
if (airportManager->airportArray != NULL)
free(airportManager->airportArray);
airportManager->airportArray == NULL;
}
// Add an airport to the manager
void addAirportByNameAndAddress(AirportManager* airportManager, char *name, char *address)
{
// Calculate the amount of memory needed
size_t mem = (airportManager->airportAmount + 1) * sizeof(Airport);
// Get the memory required
Airport* newAirports = NULL;
if (airportManager->airportArray == NULL)
newAirports = (Airport*)malloc(mem);
else
newAirports = (Airport*)realloc(airportManager->airportArray, mem);
if (newAirports == NULL)
{
// error: out of memory
return;
}
// Copy the name and the address to new the new Airport
Airport *current = newAirports + airportManager->airportAmount;
memset(current->airportName, '\0', SIZ);
strncpy(current->airportName, name, SIZ - 1);
memset(current->airportAddress, '\0', SIZ);
strncpy(current->airportAddress, address, SIZ - 1);
// Update the manager
airportManager->airportAmount++;
airportManager->airportArray = newAirports;
}
void addAirport(AirportManager* airportManager)
{
char name[SIZ] = { 0 };
char address[SIZ] = { 0 };
printf("Enter Airport Name: ");
fgets(name, SIZ - 1, stdin);
printf("Enter Airport Address: ");
fgets(address, SIZ - 1, stdin);
addAirportByNameAndAddress(airportManager, name, address);
}
void main() {
AirportManager airportManager;
initAirportManager(&airportManager);
addAirport(&airportManager);
finalAirportManager(&airportManager);
}