Examination management system

#include<stdio.h>

#include<conio.h>

void main()

{

FILE *fp, *ft;

char another, choice;

struct Exam

{       int r_no;

            char clas[20];

            char name[40];

            char add[40];

            char f_name[40];

            float math;

            float phy;

            float che;

            float comp;

            float avg;

            float avg1;

};

struct Exam f;

long int amount,flag;

long int recsize;

float avg;

int r_no;

char clas[20];

fp=fopen("EXAM.DAT","rb+");

if(fp==NULL)

{

            fp=fopen("EXAM.DAT","wb+");

            if(fp==NULL)

            {

                        puts("Cannot open file");

                        exit(1);

            }

}

recsize = sizeof(f);

while(1)

{

            clrscr();

            gotoxy(30,10);

            printf("1. Student detail");

            gotoxy(30,12);

            printf("2. Display Record");

            gotoxy(30,14);

            printf("3. Topper");

            gotoxy(30,16);

            printf("4. Failer");

            gotoxy(30,18);

            printf("5. Delete Record");

            gotoxy(30,20);

            printf("0.Exit");

            gotoxy(30,22);

            printf("Your choice");

            fflush(stdin);

            choice = getche();

            switch(choice)

            {

                        case '1':

                        fseek(fp,0,SEEK_END);

                        another = 'Y';

                        while((another == 'Y') || (another == 'y'))

                        {

                                    printf("\nEnter Roll_no");

                                    scanf("%d", &f.r_no);

                                    printf("\nEnter Name");

                                    scanf(" %s",f.name);

                                    printf("\nEnter class");

                                    scanf("%s",f.clas);

                                    printf("\nEnter Address");

                                    scanf("%s",f.add);

                                    printf("\nEnter Father name");

                                    scanf("%s",f.f_name);

                                    printf("\nEnter Maths marks ");

                                    scanf("%f", &f.math);

                                    printf("\nEnter phy marks");

                                    scanf("%f",&f.phy);

                                    printf("\nEnter che marks");

                                    scanf("%f",&f.che);

                                    printf("enter computer marks");

                                    scanf("%f",&f.comp);

                                    f.avg=f.math+f.comp+f.phy+f.che;

                                    f.avg1=f.avg/4;

                                    fwrite(&f, recsize, 1, fp);

                                    printf("\nCreate another Student Record(Y/N)");

                                    fflush(stdin);

                                    another = getche();

                        }

                        break;

                        case '2':

                        clrscr();

                        rewind(fp);

                        printf("R no   name  class  Address  Father'Nm  maths    phy    che      comp   Avg");

                        while(fread(&f, recsize, 1, fp) == 1)

                            printf("\n%d\t%s\t%s\t%s\t%s\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f", f.r_no,f.name,f.clas, f.add, f.f_name, f.math,f.phy,f.che,f.comp,f.avg1);

                        getch();

                        break;

                        case '3':

                        another='Y';

                        avg=0.0;

                        while(another=='Y')

                        {

                        printf("\nenter the class");

                        scanf("%s",clas);

                                    rewind(fp);

                                    while(fread(&f, recsize, 1, fp)==1)

                                                if((f.avg>=avg)&&(strcmp(f.clas,clas)==0))

                                                {

                                                            avg = f.avg;

                                                }

                                    printf("Student topped information is below");

                                    printf("Name = %s", f.name);

                                    fflush(stdin);

                                    another=getche();

                            }

                            break;

                        case '4':

                        another='Y';

                        avg=33.3;

                        while(another=='Y')

                        {

                                    printf("\nEnter class to check the score");

                                    scanf("%s",clas);

                                    rewind(fp);

                                    //flag=0;

                                    while(fread(&f, recsize, 1, fp)==1)

                                    {

                                                //flag=1;

                                                //printf("\n%f",f.avg1);

                                                if((strcmp(f.clas,clas)==0)&&(f.avg1<=avg))

                                                {

                                                            printf("\n failed",f.r_no);

                                                            printf("\n Students name is%s",f.name);

                                                            printf("\n Father's name is%s",f.f_name);

                                                 }

                                                            //getch();

                                    }

                                    //if(flag==0)

                                    //{

                                      //       printf("Sorry !! Invalid roll number");

                                      //       getch();

                                    //}

                                    fflush(stdin);

                                    another=getche();

                        }

                        break;

                        case '5':

                        another='Y';

                        while(another=='Y')

                        {

                                    printf("\nEnter roll number to delete");

                                    scanf("%d",&r_no);

                                    ft = fopen("TEMP.DAT","wb");

                                    rewind(fp);

                                    while(fread(&f, recsize, 1, fp) == 1)

                                    {

                                                if(f.r_no!=r_no)

                                                            fwrite(&f, recsize, 1, ft);

                                    }

                                    fclose(fp);

                                    fclose(ft);

                                    remove("EXAM.DAT");

                                    rename("TEMP.DAT", "EXAM.DAT");

                                    fp=fopen("EXAM.DAT", "rb+");

                                    printf("Delete another record(Y/N)");

                                    fflush(stdin);

                                    another = getche();

                        }

                        break;

                        case '0':

                        fclose(fp);

                        exit();

            }

}

}