OK, this is the definition of the struct:

typedef struct { int first; int last; int count; char * Array [50]; } queue; 

and I use another function to initialize it

void initialize(queue * ptr){ ptr=malloc(sizeof(queue)); ptr->first=0; ptr->last=0; ptr->count=0; } 

Then I use printf to print out first, last and count. All three should be zero. However, what I actually get is, count is 0 as I expected, but first&last are two very large strange numbers and they change every time I run the program. Can anybody tell me what's wrong here? Thank you.