Read records until end; show nth record

Design. The worker's details are held in struct worker (name, age, salary). Records are written to a binary file worker.dat with fwrite() until the user answers n to "Add another record?". Because every record has the same size, the n-th record starts at byte (n − 1) × sizeof(struct worker). fseek() jumps there and fread() reads it. A check on n prevents reading outside the file.

(For the variant, replace the members by author name, nationality and number of books.)

#include <stdio.h>

struct worker {
    char name[30];
    int age;
    float salary;
};

int main(void)
{
    FILE *fp;
    struct worker w;
    char more;
    int n, count = 0;

    fp = fopen("worker.dat", "wb");
    if (fp == NULL) {
        printf("Cannot open file\n");
        return 1;
    }
    do {
        printf("Enter name age salary: ");
        scanf("%29s %d %f", w.name, &w.age, &w.salary);
        fwrite(&w, sizeof(w), 1, fp);
        count++;
        printf("Add another record (y/n)? ");
        scanf(" %c", &more);
    } while (more == 'y' || more == 'Y');
    fclose(fp);

    printf("Enter n: ");
    scanf("%d", &n);
    if (n < 1 || n > count) {
        printf("No such record (file has %d records)\n", count);
        return 1;
    }
    fp = fopen("worker.dat", "rb");
    if (fp == NULL) {
        printf("Cannot open file\n");
        return 1;
    }
    fseek(fp, (long)(n - 1) * sizeof(w), SEEK_SET);   /* jump to nth record */
    fread(&w, sizeof(w), 1, fp);
    printf("Record %d: %s %d %.2f\n", n, w.name, w.age, w.salary);
    fclose(fp);
    return 0;
}

Sample run (three workers entered, then n = 2)

Input: Ram 30 12000 y Sita 25 15000 y Hari 41 9000 n 2

Enter name age salary: Add another record (y/n)? Enter name age salary: Add another record (y/n)? Enter name age salary: Add another record (y/n)? Enter n: Record 2: Sita 25 15000.00