Segmentation fault (code dumped) error in C - c

Question

I was trying to run this code and it is saying "Segmentation fault (code dumped)" how I can fix my code to make this error go away. here is my code so if someone could help me out that would be awesome! How can i fix my void SEARCH
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct _data {
char *name;
long number;
};
int SCAN(FILE *(*stream)){
int count = 0;
char line[256];
while (fgets(line, sizeof(line), *stream)) {
count++;
}
return count;
}
struct _data* BlackBoxLOAD(FILE **stream, int size){
struct _data* BlackBox = (struct _data*)malloc(sizeof(struct _data)*size);
int count = 0;
char line[256];
while (fgets(line, sizeof(line), *stream)) {
char* token = strtok(line, " ");
struct _data* temp = (struct _data*)malloc(sizeof(struct _data));
temp->name = token;
token = strtok(NULL, " ");
temp->number = atoi(token);
BlackBox[count] = *temp;
count++;
}
return BlackBox;
}
void SEARCH(struct _data *BlackBox, char *string, int size){
int i = 0;
for (i = 0; i<size; i++){
if (strcmp(BlackBox[i].name, string) == 0)
return i;
}
return -1;
}
void FREE(struct _data *BlackBox, int size){
free(BlackBox);
return;
}
int main(int argc, char **argv) {
int i = 0, size = 0;
FILE *stream = fopen("hw5.data", "r");
int noOfLines = SCAN(&stream);
size = noOfLines;
struct _data *BlackBox = BlackBoxLOAD(&stream, size);
fclose(stream);
for (i = 1; i<argc; i++){
if (argv[i] == "") {
printf("*******************************************");
printf("* You must include a name to search for. *");
printf("*******************************************");
}
int pos = SEARCH(BlackBox, argv[i], size);
if (pos == -1) {
printf("*******************************************");
printf("The name was NOT found.");
printf("*******************************************");
}
else{
printf("*******************************************");
printf("The name was found at the %d entry.", pos);
printf("*******************************************");
}
}
FREE(BlackBox, size);
}

Answer 1

There are just way too many bugs in this code, but here's the most obvious:
char* token = strtok(line, " ");
struct _data* temp = (struct _data*)malloc(sizeof(struct _data)*1000);
temp->name = token;
You're setting temp->name to the value of token. But token points into line, which is getting modified and will soon cease to exist because you created it on a stack that's about to go away.
You can't save a pointer to a chunk of memory that you're about to reuse.

Answer 2

After the following line has been executed
int noOfLines = SCAN(&stream);
stream is at the end of the file. You need to rewind it before you can read the data. Add the line:
frewind(stream);
after the call to SCAN.
As an aside, you should change the argument type of SCAN and BlackBoxLOAD to FILE*.
int SCAN(FILE *stream){
struct _data* BlackBoxLOAD(FILE *stream, int size){
That will make the calls easier and the functions don't have to dereference stream.
Function definition:
int SCAN(FILE *stream){
int count = 0;
char line[256];
while (fgets(line, sizeof(line), stream)) {
// Just stream, not *stream
count++;
}
return count;
}
Function call:
int noOfLines = SCAN(stream);
// Just stream, not &stream.