Try It Yourself - SyntaxStudy Editor

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#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef struct {
    char   name[32];
    int    id;
    double salary;
} Employee;

int save_employees(const char *path,
                   const Employee *arr, int n)
{
    FILE *f = fopen(path, "wb");
    if (!f) { perror(path); return -1; }

size_t written = fwrite(arr, sizeof(Employee), (size_t)n, f);
    fclose(f);
    return (written == (size_t)n) ? 0 : -1;
}

int load_employees(const char *path,
                   Employee *arr, int max, int *out_n)
{
    FILE *f = fopen(path, "rb");
    if (!f) { perror(path); return -1; }

/* Determine record count from file size */
    fseek(f, 0, SEEK_END);
    long size = ftell(f);
    rewind(f);

*out_n = (int)(size / (long)sizeof(Employee));
    if (*out_n > max) *out_n = max;

size_t read = fread(arr, sizeof(Employee), (size_t)*out_n, f);
    fclose(f);
    return (read == (size_t)*out_n) ? 0 : -1;
}

int main(void)
{
    Employee staff[] = {
        {"Alice", 1, 75000.0},
        {"Bob",   2, 68000.0},
        {"Carol", 3, 82000.0}
    };

save_employees("staff.bin", staff, 3);
    printf("Saved %d employees.
", 3);

Employee loaded[10];
    int n = 0;
    if (load_employees("staff.bin", loaded, 10, &n) == 0) {
        printf("Loaded %d employees:
", n);
        for (int i = 0; i < n; i++)
            printf("  id=%d  name=%-8s  salary=%.2f
",
                   loaded[i].id, loaded[i].name, loaded[i].salary);
    }
    return EXIT_SUCCESS;
}