How do I search a record using an integer from a file?

Question

Currently, I can only search using a string but I don't know how to search a record when the user inputs a 12 digit number (long long data type). I tried to write if(identityC == line) where the original if(strcmp(....) code was at but I didn't get it to work. Any solutions?

char line[255], name[30];
long long identityC;

FILE* fpointer = fopen("123 Hotel Customer.txt", "r");

//printf("\nPlease Enter Your Identity Card Number: ");
//scanf("%lld", &identityC);

printf("\nPlease Enter your Name to Search your Room Booking: ");
scanf("%s", &name);

while (!feof(fpointer))
{
    fgets(line, 255, fpointer);
    
    if (strncmp(name, line, strlen(name)) == 0)
        printf("%s", line);
} 

fclose(fpointer);

return;

Please clarify exactly what you want your code to do, and what isnt working. Like this right now, we wont be able to help you — Jakob Sachs, Jul 13 '21 at 11:54
Not your question, but see [Why is `while ( !feof (file) )` always wrong?](https://stackoverflow.com/questions/5431941) — Steve Summit, Jul 13 '21 at 11:57
You can always "print" the number to a string, then use the string as you already do. — pmg, Jul 13 '21 at 11:58
What does the file `123 Hotel Customer.txt` look like inside? How are the customer name, identity card numbers, and other fields represented? — Steve Summit, Jul 13 '21 at 11:59
I believe this might be your solution: https://stackoverflow.com/a/15757280/16397750 — ankit_acharya, Jul 13 '21 at 12:04
`if (identityC == line)`: `identityC ` is a `long long` and `line` is an array of `char`. What makes you think that the comparision is valid? Didn't you get any compiler warnings? — Jabberwocky, Jul 13 '21 at 12:13
By using `strncmp` you'll get a false match between say `"Weather"` and `"WeatherVane..."`. — Weather Vane, Jul 13 '21 at 12:17

Daoist Paul · Answer 1 · 2021-07-13T16:16:19.563

Note: The purpose is to show a way to get started with working with files.

Assuming you store information in your file in this format,

roomno,Hotel Name,Customer name,isOccupied
datatype: int, string, string, bool

you can do this-

FILE* file = fopen("filename.txt","w");
char buffer[512];
while(fgets(buffer, 512, file)!=NULL){
  int roomNo = strtok(buffer, "\n,");
  char* hotel_name = strtok(NULL, "\n,");
  char* customer_name = strtok(NULL, "\n,");
  bool isOccupied = strtok(NULL, "\n,");
// Now you are done extracting values from file. Now do any work with them.
}

Here is information on strtok() and fgets().

Also, from Steve Summit, Why is while (!feof (file) ) always wrong?

How do I search a record using an integer from a file?

1 Answers1