C program to create student database using structures and files

Write a C program to create student database using files and structure.

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

  /* student structure */
  struct student {
        char name[32];
        int age, rollNo;
        int m1, m2, m3;
        float average;
  };

  int main(int argc, char *argv[]) {
        struct student s1;
        int i, n, m1, m2, m3, age, flag, rollNo;
        char name[32];
        float average;
        FILE *fp;

        /* open the given input file in write mode  */
        fp = fopen(argv[1], "w");

        /* get the number of students from the user */
        printf("Enter the number of students:");
        scanf("%d", &n);

        /* get student information from user and write it to a file */

        for (i = 0; i < n; i++) {

                printf("\nEnter student %d details:\n", i + 1);

                getchar();

                printf("Name: ");

                fgets(name, 32, stdin);

                name[strlen(name) - 1] = '\0';

                printf("Roll Number: ");

                scanf("%d", &rollNo);

                printf("Age: ");

                scanf("%d", &age);

                printf("Mark1, Mark2, Mark3:");

                scanf("%d%d%d", &m1, &m2, &m3);

                average = (1.0 * (m1 + m2 + m3)) / 3;

                /* writing student information to a file  */

                fprintf(fp, "%d %s %d %d %d %d %f\n",

                        rollNo, name, age, m1, m2, m3, average);

        }

        /* closing the opened file */

        fclose(fp);

        /* opening the input file in read mode */

        fp = fopen(argv[1], "r");

        /*

         * fetches the desired student record from

         * file and displays it to the user 

         */

        while (1) {

                printf("\nEnter the desired student roll number:");

                scanf("%d", &rollNo);

                flag = 0;

                while (!feof(fp)) {

                        fscanf(fp, "%d %s %d %d %d %d %f", &s1.rollNo,

                                s1.name, &s1.age, &s1.m1, &s1.m2, 
                                              &s1.m3, &s1.average);

                        if (s1.rollNo == rollNo) {

                                printf("Details of %s:\n", s1.name);

                                printf("RollNo: %d\n", s1.rollNo);

                                printf("Age: %d\n", s1.age);

                                printf("Mark1: %d\n", s1.m1);

                                printf("Mark2: %d\n", s1.m2);

                                printf("Mark3: %d\n", s1.m3);

                                printf("Average: %f\n", s1.average);

                                flag = 1;

                                break;

                        }

                }

                if (!flag) {

                        printf("Record Not Found!!\n");

                }

                /* rewinding the file pointer to the start of file */

                rewind(fp);

                printf("Do you want to continue(1/0):");

                scanf("%d", &flag);

                if (!flag)

                        break;

        }

        /* closing the file */

        fclose(fp);

        return(0);

  }

Note:
./a.out  studentDB.txt => passing file name(studentDB.txt) in command line.

  Output:

  jp@jp-VirtualBox:~/$ ./a.out   studentDB.txt 
  Enter the number of students:3

  Enter student 1 details:
  Name: Ram
  Roll Number: 101
  Age: 10
  Mark1, Mark2, Mark3:100 100 100

  Enter student 2 details:
  Name: Sam
  Roll Number: 102
  Age: 10
  Mark1, Mark2, Mark3:95 96 97

  Enter student 3 details:
  Name: Tom
  Roll Number: 103
  Age: 10
  Mark1, Mark2, Mark3:95 97 99

  Enter the desired student roll number:101
  Details of Ram:
  RollNo: 101
  Age: 10
  Mark1: 100
  Mark2: 100
  Mark3: 100
  Average: 100.000000
  Do you want to continue(1/0):1

  Enter the desired student roll number:103
  Details of Tom:
  RollNo: 103
  Age: 10
  Mark1: 95
  Mark2: 97
  Mark3: 99
  Average: 97.000000
  Do you want to continue(1/0):0

  jp@jp-VirtualBox:~/$ cat studentDB.txt 
  101 Ram 10 100 100 100 100.000000
  102 Sam 10   95  96   97  96.000000
  103 Tom 10  95  97   99   97.000000