malloc

Hey guys im loading some data from a file into memory using the structs.. i need to allocate some memory for it using malloc but im unsure which variables i need to use to allocate memory for the structs.

could someone also explain a little more about the structs

Code:

typedef struct category* CategoryTypePtr;
typedef struct item* ItemTypePtr;

/* Structure definitions. */
typedef struct price
{
   unsigned dollars;
   unsigned cents;
} PriceType;

typedef struct item
{
   char itemID[ID_LEN + 1];
   char itemName[MAX_NAME_LEN + 1];
   PriceType prices[NUM_PRICES];
   char itemDescription[MAX_DESC_LEN];
   ItemTypePtr nextItem;
} ItemType;

typedef struct category
{
   char categoryID[ID_LEN + 1];
   char categoryName[MAX_NAME_LEN + 1];
   char drinkType;      /* (H)ot or (C)old. */
   char categoryDescription[MAX_DESC_LEN];
   CategoryTypePtr nextCategory;
   ItemTypePtr headItem;
   unsigned numItems;
} CategoryType;

typedef struct gjc
{
   CategoryTypePtr headCategory;
   unsigned numCategories;
} GJCType;

You need to malloc() memory for each structure so make a pointer.

Code:

int main(){
     GJCType *name;
     name = malloc(sizeof(GJCType));
     name -> headCategory = malloc( sizeof(CategoryType) );
     name -> headCategory -> headItem=malloc( sizeof(ItemType) );
     name -> headCategory -> nextCategory = malloc( sizeof(CategoryType) );
     name -> headCategory -> headItem -> nextItem = malloc( sizeof(ItemType) );
}

And so on...
~Sven

And don't forget to make type casting!Because malloc() return a *void

Originally Posted by fnoyan

And don't forget to make type casting!Because malloc() return a *void

What are you referring to? Casting the return value of malloc?
C does type coercian from void to any other type automatically so casting malloc only has the potential of evil side-effects.