Question

about the code:

tp is a pointer to a certain struct which contains a table.

the table is a pointer to a pointer of a differnt struct,used as an array.

size is just the size of the table.

im sending these veriables to a function in order to initialize all the cells in the

array to NULL.

this line:

initArr(tp->table,tp->size);

sends them to this function:

 void initArr(ObjectP* array,int size)
 {
    int i;
    for (i = 0; i < size; ++i)
    {
        array[i]=NULL;
    }
 }

using the eclipse debugger i can see that the objects in the array are infact

being initialized to NULL, but when the method ends,

tp->table is NULL.

pointers gone wild?

help please.

the structs:

table:

  typedef struct Table
    {
        size_t size;
        hashFcn hash;
        printFcn print;
        comparisonFcn comp;
        ObjectP* table;
        int duplicated;
    }Table;

object:

    typedef struct Object
    {
         void *key;
         ObjectP pointsTo;
    }Object;

Answer 1

Arrays and pointers are similar but different.

An array of pointers can be represented as a number of continuous pointers in memory (with an address of where the first pointer in the array resides).

Under such a circumstance tp->table is exactly the same as tp->table[0], but the [0] is assumed (because it has the same address). In systems that are implemented in this manner, the tp->table specifies an address, and the offset from that address (to get to the element of the array) is represented as a value times the datatype size (or one pointer’s size in your case).

tp->table (the base address 0x00000100)
tp->table[0] (the address 0x00000100 + 0 * sizeof(... pointer ...) = 0x00000100)
tp->table[1] (the address 0x00000100 + 1 * sizeof(... pointer ...) = 0x00000104 (some systems only))
tp->table[2] (the address 0x00000100 + 2 * sizeof(... pointer ...) = 0x00000108 (some systems only))

So your debugger might actually be printing out tp->table which is exactly equivalent to tp->table[0] depending on your compiler’s implementation.