1. Writing the data in binary file
2. Reading the data from binary file
3. Modify the record
4. Delete the record

//A menu-driven program for elementary database management
#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
#include <windows.h>
#include <string.h>
COORD coord = {0,0};
void gotoxy(int x,int y){
    coord.X = x; coord.Y = y;
    SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE),coord);
}
int main(){
    FILE *fp, *ft;
    char another, choice;
    struct emp{
        char name[40];
        int age;
        float bs;
    };
    struct emp e;
    char empname[40];
    long int recsize;
    fp = fopen("EMP.DAT","rb+");
    if(fp == NULL){
        fp = fopen("EMP.DAT","wb+");
        if(fp == NULL){
            printf("Connot open file");
            exit(1);
        }
    }
    recsize = sizeof(e);
    while(1){
        system("cls");
        gotoxy(30,10);
        printf("1. Add Record");
        gotoxy(30,12);
        printf("2. List Records");
        gotoxy(30,14);
        printf("3. Modify Records");
        gotoxy(30,16);
        printf("4. Delete Records");
        gotoxy(30,18);
        printf("5. Exit");
        gotoxy(30,20);
        printf("Your Choice: ");
        fflush(stdin);
        choice  = getche();
        switch(choice){
            case '1':
                system("cls");
                fseek(fp,0,SEEK_END);
                another = 'y';
                while(another == 'y'){
                    printf("\nEnter name,age and basic salary");
                    scanf("%s%d%f",e.name, &e.age, &e.bs);
                    fwrite(&e,recsize,1,fp);
                    printf("\nAdd another record(y/n) ");
                    fflush(stdin);
                    another = getche();
                }
                break;
            case '2':
                system("cls");
                rewind(fp);
                while(fread(&e,recsize,1,fp)==1){
                    printf("\n%s %d %.2f",e.name,e.age,e.bs);
                }
                getch();
                break;
            case '3':
                system("cls");
                another = 'y';
                while(another == 'y'){
                    printf("Enter the employee name to modify: ");
                    scanf("%s", empname);
                    rewind(fp);
                    while(fread(&e,recsize,1,fp)==1){
                        if(strcmp(e.name,empname) == 0){
                            printf("\nEnter new name,age and bs");
                            scanf("%s%d%f",e.name,&e.age,&e.bs);
                            fseek(fp,-recsize,SEEK_CUR);
                            fwrite(&e,recsize,1,fp);
                            break;
                        }
                    }
                    printf("\nModify another record(y/n)");
                    fflush(stdin);
                    another = getche();
                }
                break;
            case '4':
                system("cls");
                another = 'y';
                while(another == 'y'){
                    printf("\nEnter name of employee to delete ");
                    scanf("%s",empname);
                    ft = fopen("Temp.dat","wb");
                    rewind(fp);
                    while(fread(&e,recsize,1,fp) == 1){
                        if(strcmp(e.name,empname) != 0){
                            fwrite(&e,recsize,1,ft);
                        }
                    }
                    fclose(fp);
                    fclose(ft);
                    remove("EMP.DAT");
                    rename("Temp.dat","EMP.DAT");
                    fp = fopen("EMP.DAT", "rb+");
                    printf("Delete another record(y/n)");
                    fflush(stdin);
                    another = getche();
                }
                break;
            case '5':
                fclose(fp);
                exit(0);
        }
    }
    return 0;
}