luc091.c

Metadata

• Author — Amit Dutta
• Last updated — 08 Feb 2026
• License — MIT License (See the LICENSE file for details)

Problem Statement

Problem Statement

Read 'blood donors' file (Name, Address, Age, Blood Type). Print donors with Age < 25 and Blood Type 2.

Source Code

View on GitHub Download Raw

Printing the code

To print this file, open it on GitHub and click Raw before printing, or use the Download Raw button above and print directly from that page.

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

struct donor {
    char name[21];    // 20 cols + null
    char address[41]; // 40 cols + null
    int age;          // 2 cols -> int
    int blood_type;   // 1 col -> int
};

void create_donor_file();

int main()
{
    FILE *fp;
    struct donor d;

    create_donor_file();

    fp = fopen("donors.dat", "rb");
    if (!fp)
    {
        printf("File error.\n");
        exit(1);
    }

    printf("--- Donors (Age < 25, Type 2) ---\n");
    while (fread(&d, sizeof(struct donor), 1, fp) == 1)
    {
        if (d.age < 25 && d.blood_type == 2)
        {
            printf("Name: %s | Age: %d | Addr: %s\n", d.name, d.age, d.address);
        }
    }

    fclose(fp);
    return 0;
}

void create_donor_file()
{
    struct donor data[] = {
        {"Amit", "Delhi", 22, 2},   // Match
        {"Rahul", "Mumbai", 30, 2}, // Old
        {"Sumit", "Pune", 21, 1},   // Wrong type
        {"Priya", "Goa", 24, 2}     // Match
    };
    FILE *f = fopen("donors.dat", "wb");
    fwrite(data, sizeof(struct donor), 4, f);
    fclose(f);
}