#include <stdio.h>
#include <stdlib.h>
 
struct Student {
    int roll;
    char name[50];
    float marks;
};
 
int main() {
    FILE *file;
    struct Student s;
    int n, i;
 
    // Step 1: Open file in write mode
    file = fopen("students.txt", "w");
 
    if (file == NULL) {
        printf("Error! Cannot open file.\n");
        return 1;
    }
 
    // Step 2: Get number of students
    printf("Enter number of students: ");
    scanf("%d", &n);
 
    // Step 3: Get and write student records
    for (i = 0; i < n; i++) {
        printf("\nEnter details of student %d\n", i + 1);
        printf("Roll Number: ");
        scanf("%d", &s.roll);
        printf("Name: ");
        scanf("%s", s.name);
        printf("Marks: ");
        scanf("%f", &s.marks);
 
        fprintf(file, "%d %s %.2f\n", s.roll, s.name, s.marks);
    }
 
    fclose(file);
    printf("\nStudent records stored successfully in 'students.txt'.\n");
 
    // Step 4: Reopen file to display contents
    file = fopen("students.txt", "r");
 
    if (file == NULL) {
        printf("Error! Cannot open file.\n");
        return 1;
    }
 
    printf("\n--- Student Records ---\n");
    while (fscanf(file, "%d %s %f", &s.roll, s.name, &s.marks) != EOF) {
        printf("Roll: %d\tName: %s\tMarks: %.2f\n", s.roll, s.name, s.marks);
    }
 
    fclose(file);
    return 0;
}