C :: Array Of Structs (adding / Deleting Elements To A File)

I want to write a program to record my neighborhoods's name and address by using an array of structs and file.

my array of structs is

Code:
#define SIZE 30
typedef struct{
char name[30];
char address[100];
}Detail;
Detail neighbor[SIZE];

And I want to make adding,deleting, and searching functions.Something like

Code:

void add();//Add name and address to a file,
//and add more to the same file if I want to.
void del();//Delete or Change some neighbor's name or address
//in the same file(Can I?)
void search();//Search name and show detail

So I started to code adding function first, but I don't know that I need to use pointer to code each functions relations, and I don't know how to check that my input's already exists yet. But I started some code below...

Code:
void add() {
int i=0;
FILE *fp = fopen("neighborhood.txt", "at");
if ( fp != NULL ) {
do{

[Code]......