The mini-project “Library management system project in C” is a console application using the C programming language. This project compiled in Code Blocks with the GCC compiler. In this console application, you can do basic library management task like adding the book, view the added book, search the books, ..etc.

This application based on file handling in C, where I have used a file-related function like fopen, fread, fwrite, ..etc. Good thing is that “Library management system project” is password-protected, so only authorized person able to login in this application.

Also to increase the redabilty I have broken the application in different function. Each function of the project extensively use the file handing function, so it is also a great project to understand file handling.

Note: Don’t copy and paste the code for your project. Use the code to learn and do the project yourself.

List of a function used in “Library management system project in C”

isFileExists():

This function verifies that a file has been created or not. If the file exists, the function return 1 otherwise returns 0.

int isFileExists(const char *path)
{
    // Try to open file
    FILE *fp = fopen(path, "rb");
    int status = 0;

    // If file does not exists
    if (fp != NULL)
    {
        status = 1;
        // File exists hence close file
        fclose(fp);
    }

    return status;
}

init():

This function creates the file if not exist and copies the default password (“aticleworld”) in file header structure.

void init()
{
    FILE *fp = NULL;
    int status = 0;
    const char defaultUsername[] ="aticleworld\n";
    const char defaultPassword[] ="aticleworld\n";

    sFileHeader fileHeaderInfo = {0};

    status = isFileExists(FILE_NAME);

    if(!status)
    {
        //create the binary file
        fp = fopen(FILE_NAME,"wb");
        if(fp != NULL)
        {
            //Copy default password
            strncpy(fileHeaderInfo.password,defaultPassword,sizeof(defaultPassword));
            strncpy(fileHeaderInfo.username,defaultUsername,sizeof(defaultUsername));
            fwrite(&fileHeaderInfo,FILE_HEADER_SIZE, 1, fp);

            fclose(fp);
        }
    }
}

printMessageCenter():

This function prints the message in the middle of the head massage. I have passed the message in this function as per the operation.

void printMessageCenter(const char* message)
{
    int len =0;
    int pos = 0;

    //calculate how many space need to print
    len = (78 - strlen(message))/2;
    printf("\t\t\t");
    for(pos =0 ; pos < len ; pos++)
    {
        //print space
        printf(" ");
    }
    //print message
    printf("%s",message);

}

headMessage():

It prints the message on the top of the console and prints the message as per operation.

void headMessage(const char *message)
{
    system("cls");
    printf("\t\t\t###########################################################################");
    printf("\n\t\t\t############                                                   ############");
    printf("\n\t\t\t############      Library management System Project in C       ############");
    printf("\n\t\t\t############                                                   ############");
    printf("\n\t\t\t###########################################################################");
    printf("\n\t\t\t---------------------------------------------------------------------------\n");
    printMessageCenter(message);
    printf("\n\t\t\t----------------------------------------------------------------------------");

}

welcomeMessage():

This function displays the first welcomes screen of the “Library management system project” and asks the user to press any key to access the library application.

void welcomeMessage()
{
    headMessage("www.aticleworld.com");
    printf("\n\n\n\n\n");
    printf("\n\t\t\t  **-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**\n");
    printf("\n\t\t\t        =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=");
    printf("\n\t\t\t        =                 WELCOME                   =");
    printf("\n\t\t\t        =                   TO                      =");
    printf("\n\t\t\t        =                 LIBRARY                   =");
    printf("\n\t\t\t        =               MANAGEMENT                  =");
    printf("\n\t\t\t        =                 SYSTEM                    =");
    printf("\n\t\t\t        =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=");
    printf("\n\t\t\t  **-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**\n");
    printf("\n\n\n\t\t\t Enter any key to continue.....");
    getch();
}

isNameValid():

It validates the user name, author name ..etc. I have permitted this function to take the space in names.

int isNameValid(const char *name)
{
    int validName = 1;
    int len = 0;
    int index = 0;

    len = strlen(name);

    for(index =0; index <len ; ++index)
    {
        if(!(isalpha(name[index])) && (name[index] != '\n') && (name[index] != ' '))
        {
            validName = 0;
            break;
        }
    }
    return validName;
}

isValidDate():

This function read the date in the format of dd/mm/yyyy also it validates the entered date.

// Function to check leap year.
//Function returns 1 if leap year
int  IsLeapYear(int year)
{
    return (((year % 4 == 0) &&
             (year % 100 != 0)) ||
            (year % 400 == 0));
}

// returns 1 if given date is valid.
int isValidDate(Date *validDate)
{
    //check range of year,month and day
    if (validDate->yyyy > MAX_YR ||
            validDate->yyyy < MIN_YR)
        return 0;
    if (validDate->mm < 1 || validDate->mm > 12)
        return 0;
    if (validDate->dd < 1 || validDate->dd > 31)
        return 0;

    //Handle feb days in leap year
    if (validDate->mm == 2)
    {
        if (IsLeapYear(validDate->yyyy))
            return (validDate->dd <= 29);
        else
            return (validDate->dd <= 28);
    }

    //handle months which has only 30 days
    if (validDate->mm == 4 || validDate->mm == 6 ||
            validDate->mm == 9 || validDate->mm == 11)
        return (validDate->dd <= 30);

    return 1;
}

menu():

This function displays the library menu and asks the user to select the option. If the user selects 0, then the application will close.

void menu()
{
    int choice = 0;
    do
    {
        headMessage("MAIN MENU");
        printf("\n\n\n\t\t\t1.Add Books");
        printf("\n\t\t\t2.Search Books");
        printf("\n\t\t\t3.View Books");
        printf("\n\t\t\t4.Delete Book");
        printf("\n\t\t\t5.Update Password");
        printf("\n\t\t\t0.Exit");
        printf("\n\n\n\t\t\tEnter choice => ");

        scanf("%d",&choice);
        switch(choice)
        {
        case 1:
            addBookInDataBase();
            break;
        case 2:
            searchBooks();
            break;
        case 3:
            viewBooks();
            break;
        case 4:
            deleteBooks();
            break;
        case 5:
            updateCredential();
            break;
        case 0:
            printf("\n\n\n\t\t\t\tThank you!!!\n\n\n\n\n");
            exit(1);
            break;
        default:
            printf("\n\n\n\t\t\tINVALID INPUT!!! Try again...");
        }																						//Switch Ended
    }
    while(choice!=0);																				//Loop Ended
}

addBookInDataBase():

This function opens the binary file in append mode and writes the book and the details.

// Add books in list
void addBookInDataBase()
{
    int days;
    s_BooksInfo addBookInfoInDataBase = {0};
    FILE *fp = NULL;
    int status = 0;
    fp = fopen(FILE_NAME,"ab+");
    if(fp == NULL)
    {
        printf("File is not opened\n");
        exit(1);
    }
    headMessage("ADD NEW BOOKS");

    printf("\n\n\t\t\tENTER YOUR DETAILS BELOW:");
    printf("\n\t\t\t---------------------------------------------------------------------------\n");
    printf("\n\t\t\tBook ID NO  = ");
    fflush(stdin);
    scanf("%u",&addBookInfoInDataBase.books_id);
    do
    {
        printf("\n\t\t\tBook Name  = ");
        fflush(stdin);
        fgets(addBookInfoInDataBase.bookName,MAX_BOOK_NAME,stdin);

        status = isNameValid(addBookInfoInDataBase.bookName);
        if (!status)
        {
            printf("\n\t\t\tName contain invalid character. Please enter again.");
        }
    }
    while(!status);

    do
    {
        printf("\n\t\t\tAuthor Name  = ");
        fflush(stdin);
        fgets(addBookInfoInDataBase.authorName,MAX_AUTHOR_NAME,stdin);

        status = isNameValid(addBookInfoInDataBase.authorName);
        if (!status)
        {
            printf("\n\t\t\tName contain invalid character. Please enter again.");
        }
    }
    while(!status);


    do
    {
        printf("\n\t\t\tStudent Name  = ");
        fflush(stdin);
        fgets(addBookInfoInDataBase.studentName,MAX_STUDENT_NAME,stdin);

        status = isNameValid(addBookInfoInDataBase.studentName);
        if (!status)
        {
            printf("\n\t\t\tName contain invalid character. Please enter again.");
        }
    }
    while(!status);

    do
    {
        //get date year,month and day from user
        printf("\n\t\t\tEnter date in format (day/month/year): ");
        scanf("%d/%d/%d",&addBookInfoInDataBase.bookIssueDate.dd,&addBookInfoInDataBase.bookIssueDate.mm,&addBookInfoInDataBase.bookIssueDate.yyyy);

        //check date validity
        status = isValidDate(&addBookInfoInDataBase.bookIssueDate);
        if (!status)
        {
            printf("\n\t\t\tPlease enter a valid date.\n");
        }
    }
    while(!status);

    fwrite(&addBookInfoInDataBase,sizeof(addBookInfoInDataBase), 1, fp);
    fclose(fp);

}

searchBooks():

This function opens the binary file in reading mode and asks the user to enter the book name which wants to search.  If the book is not available in the list, it shows the message book not find in records.

void searchBooks()
{
    int found = 0;
    char bookName[MAX_BOOK_NAME] = {0};
    s_BooksInfo addBookInfoInDataBase = {0};
    FILE *fp = NULL;
    int status = 0;
    fp = fopen(FILE_NAME,"rb");
    if(fp == NULL)
    {
        printf("\n\t\t\tFile is not opened\n");
        exit(1);
    }

    headMessage("SEARCH BOOKS");
    //put the control on books detail
    if (fseek(fp,FILE_HEADER_SIZE,SEEK_SET) != 0)
    {
        fclose(fp);
        printf("\n\t\t\tFacing issue while reading file\n");
        exit(1);
    }

    printf("\n\n\t\t\tEnter Book Name to search:");
    fflush(stdin);
    fgets(bookName,MAX_BOOK_NAME,stdin);

    while (fread (&addBookInfoInDataBase, sizeof(addBookInfoInDataBase), 1, fp))
    {
        if(!strcmp(addBookInfoInDataBase.bookName, bookName))
        {
            found = 1;
            break;
        }

    }

    if(found)
    {
        printf("\n\t\t\tBook id = %u\n",addBookInfoInDataBase.books_id);
        printf("\t\t\tBook name = %s",addBookInfoInDataBase.bookName);
        printf("\t\t\tBook authorName = %s",addBookInfoInDataBase.authorName);
        printf("\t\t\tBook issue date(day/month/year) =  (%d/%d/%d)",addBookInfoInDataBase.bookIssueDate.dd,
               addBookInfoInDataBase.bookIssueDate.mm, addBookInfoInDataBase.bookIssueDate.yyyy);
    }
    else
    {
        printf("\n\t\t\tNo Record");
    }

    fclose(fp);
    printf("\n\n\n\t\t\tPress any key to go to main menu.....");
    getchar();
}

viewBooks():

It opens the file in reading mode and read and display all the stored book details. If there is no book available in the records, then it displays the message record is empty.

// view all books function
void viewBooks()
{
    int found = 0;
    char bookName[MAX_BOOK_NAME] = {0};
    s_BooksInfo addBookInfoInDataBase = {0};
    FILE *fp = NULL;
    int status = 0;
    unsigned int countBook = 1;

    headMessage("VIEW BOOKS DETAILS");
    fp = fopen(FILE_NAME,"rb");
    if(fp == NULL)
    {
        printf("File is not opened\n");
        exit(1);
    }
    if (fseek(fp,FILE_HEADER_SIZE,SEEK_SET) != 0)
    {
        fclose(fp);
        printf("Facing issue while reading file\n");
        exit(1);
    }

    while (fread (&addBookInfoInDataBase, sizeof(addBookInfoInDataBase), 1, fp))
    {
        printf("\n\t\t\tBook Count = %d\n\n",countBook);
        printf("\t\t\tBook id = %u",addBookInfoInDataBase.books_id);
        printf("\n\t\t\tBook name = %s",addBookInfoInDataBase.bookName);
        printf("\t\t\tBook authorName = %s",addBookInfoInDataBase.authorName);
        printf("\t\t\tBook issue date(day/month/year) =  (%d/%d/%d)",addBookInfoInDataBase.bookIssueDate.dd,
               addBookInfoInDataBase.bookIssueDate.mm, addBookInfoInDataBase.bookIssueDate.yyyy);
        found = 1;
        ++countBook;
    }
    fclose(fp);

    if(!found)
    {
        printf("\n\t\t\tNo Record");
    }
    printf("\n\n\t\t\tPress any key to go to main menu.....");

    fflush(stdin);
    getchar();

}

deleteBooks():

This function asks the book id from the user for the book want to delete. In this function, I am creating a temporary binary file and copy all the data from the existing file except the book whose book id entered by the user. In the last renamed the temporary bin file with an existing binary file.

void deleteBooks()
{
    int found = 0;
    int bookDelete = 0;
    sFileHeader fileHeaderInfo = {0};
    char bookName[MAX_BOOK_NAME] = {0};
    s_BooksInfo addBookInfoInDataBase = {0};
    FILE *fp = NULL;
    FILE *tmpFp = NULL;
    int status = 0;

    headMessage("Delete Books Details");

    fp = fopen(FILE_NAME,"rb");
    if(fp == NULL)
    {
        printf("File is not opened\n");
        exit(1);
    }

    tmpFp = fopen("tmp.bin","wb");
    if(tmpFp == NULL)
    {
        fclose(fp);
        printf("File is not opened\n");
        exit(1);
    }

    fread (&fileHeaderInfo,FILE_HEADER_SIZE, 1, fp);
    fwrite(&fileHeaderInfo,FILE_HEADER_SIZE, 1, tmpFp);


    printf("\n\t\t\tEnter Book ID NO. for delete:");
    scanf("%d",&bookDelete);


    while (fread (&addBookInfoInDataBase, sizeof(addBookInfoInDataBase), 1, fp))
    {
        if(addBookInfoInDataBase.books_id != bookDelete)
        {
            fwrite(&addBookInfoInDataBase,sizeof(addBookInfoInDataBase), 1, tmpFp);
        }
        else
        {
            found = 1;
        }
    }

    (found)? printf("\n\t\t\tRecord deleted successfully....."):printf("\n\t\t\tRecord not found");

    fclose(fp);
    fclose(tmpFp);
    remove(FILE_NAME);
    rename("tmp.bin",FILE_NAME);

}

updateCredential():

This function opens the file in rb+ mode (reading and writing). It asks the user for the new username and password. After taking the password and username it closes the application. Now user can use the application with a new password and username.

void updateCredential(void)
{
    sFileHeader fileHeaderInfo = {0};
    FILE *fp = NULL;
    unsigned char userName[MAX_SIZE_USER_NAME] = {0};
    unsigned char password[MAX_SIZE_PASSWORD] = {0};

    headMessage("Update Credential");

    fp = fopen(FILE_NAME,"rb+");
    if(fp == NULL)
    {
        printf("File is not opened\n");
        exit(1);
    }

    fread (&fileHeaderInfo,FILE_HEADER_SIZE, 1, fp);
    if (fseek(fp,0,SEEK_SET) != 0)
    {
        fclose(fp);
        printf("\n\t\t\tFacing issue while updating password\n");
        exit(1);
    }

    printf("\n\n\t\t\tNew Username:");
    fflush(stdin);
    fgets(userName,MAX_SIZE_USER_NAME,stdin);

    printf("\n\n\t\t\tNew Password:");
    fflush(stdin);
    fgets(password,MAX_SIZE_PASSWORD,stdin);

    strncpy(fileHeaderInfo.username,userName,sizeof(userName));
    strncpy(fileHeaderInfo.password,password,sizeof(password));
    fwrite(&fileHeaderInfo,FILE_HEADER_SIZE, 1, fp);

    fclose(fp);

    printf("\n\t\t\tYour Password has been changed successfully");
    printf("\n\t\t\ttLogin Again:");
    fflush(stdin);
    getchar();
    exit(1);
}

Complete code of Library management system project in C:

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

#define MAX_YR  9999
#define MIN_YR  1900

#define MAX_SIZE_USER_NAME 30
#define MAX_SIZE_PASSWORD  20
#define FILE_NAME  "AticleworldLibBookS.bin"

// Macro related to the books info
#define MAX_BOOK_NAME   50
#define MAX_AUTHOR_NAME 50
#define MAX_STUDENT_NAME 50
#define MAX_STUDENT_ADDRESS 300


#define FILE_HEADER_SIZE  sizeof(sFileHeader)


//structure to store date
typedef struct
{
    int yyyy;
    int mm;
    int dd;
} Date;


typedef struct
{
    char username[MAX_SIZE_USER_NAME];
    char password[MAX_SIZE_PASSWORD];
} sFileHeader;


typedef struct// to call in program
{
    unsigned int books_id; // declare the integer data type
    char bookName[MAX_BOOK_NAME];// declare the character data type
    char authorName[MAX_AUTHOR_NAME];// declare the charecter data type
    char studentName[MAX_STUDENT_NAME];// declare the character data type
    char studentAddr[MAX_STUDENT_ADDRESS];// declare the character data type
    Date bookIssueDate;// declare the integer data type
} s_BooksInfo;

void printMessageCenter(const char* message)
{
    int len =0;
    int pos = 0;

    //calculate how many space need to print
    len = (78 - strlen(message))/2;
    printf("\t\t\t");
    for(pos =0 ; pos < len ; pos++)
    {
        //print space
        printf(" ");
    }
    //print message
    printf("%s",message);

}

void headMessage(const char *message)
{
    system("cls");
    printf("\t\t\t###########################################################################");
    printf("\n\t\t\t############                                                   ############");
    printf("\n\t\t\t############      Library management System Project in C       ############");
    printf("\n\t\t\t############                                                   ############");
    printf("\n\t\t\t###########################################################################");
    printf("\n\t\t\t---------------------------------------------------------------------------\n");
    printMessageCenter(message);
    printf("\n\t\t\t----------------------------------------------------------------------------");

}



void welcomeMessage()
{

    headMessage("www.aticleworld.com");
    printf("\n\n\n\n\n");
    printf("\n\t\t\t  **-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**\n");
    printf("\n\t\t\t        =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=");
    printf("\n\t\t\t        =                 WELCOME                   =");
    printf("\n\t\t\t        =                   TO                      =");
    printf("\n\t\t\t        =                 LIBRARY                   =");
    printf("\n\t\t\t        =               MANAGEMENT                  =");
    printf("\n\t\t\t        =                 SYSTEM                    =");
    printf("\n\t\t\t        =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=");
    printf("\n\t\t\t  **-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**-**\n");
    printf("\n\n\n\t\t\t Enter any key to continue.....");
    getch();
}


int isNameValid(const char *name)
{
    int validName = 1;
    int len = 0;
    int index = 0;

    len = strlen(name);

    for(index =0; index <len ; ++index)
    {
        if(!(isalpha(name[index])) && (name[index] != '\n') && (name[index] != ' '))
        {
            validName = 0;
            break;
        }
    }
    return validName;
}

// Function to check leap year.
//Function returns 1 if leap year
int  IsLeapYear(int year)
{
    return (((year % 4 == 0) &&
             (year % 100 != 0)) ||
            (year % 400 == 0));
}

// returns 1 if given date is valid.
int isValidDate(Date *validDate)
{
    //check range of year,month and day
    if (validDate->yyyy > MAX_YR ||
            validDate->yyyy < MIN_YR)
        return 0;
    if (validDate->mm < 1 || validDate->mm > 12)
        return 0;
    if (validDate->dd < 1 || validDate->dd > 31)
        return 0;

    //Handle feb days in leap year
    if (validDate->mm == 2)
    {
        if (IsLeapYear(validDate->yyyy))
            return (validDate->dd <= 29);
        else
            return (validDate->dd <= 28);
    }

    //handle months which has only 30 days
    if (validDate->mm == 4 || validDate->mm == 6 ||
            validDate->mm == 9 || validDate->mm == 11)
        return (validDate->dd <= 30);

    return 1;
}





// Add books in list
void addBookInDataBase()
{
    int days;
    s_BooksInfo addBookInfoInDataBase = {0};
    FILE *fp = NULL;
    int status = 0;
    fp = fopen(FILE_NAME,"ab+");
    if(fp == NULL)
    {
        printf("File is not opened\n");
        exit(1);
    }
    headMessage("ADD NEW BOOKS");

    printf("\n\n\t\t\tENTER YOUR DETAILS BELOW:");
    printf("\n\t\t\t---------------------------------------------------------------------------\n");
    printf("\n\t\t\tBook ID NO  = ");
    fflush(stdin);
    scanf("%u",&addBookInfoInDataBase.books_id);
    do
    {
        printf("\n\t\t\tBook Name  = ");
        fflush(stdin);
        fgets(addBookInfoInDataBase.bookName,MAX_BOOK_NAME,stdin);

        status = isNameValid(addBookInfoInDataBase.bookName);
        if (!status)
        {
            printf("\n\t\t\tName contain invalid character. Please enter again.");
        }
    }
    while(!status);

    do
    {
        printf("\n\t\t\tAuthor Name  = ");
        fflush(stdin);
        fgets(addBookInfoInDataBase.authorName,MAX_AUTHOR_NAME,stdin);

        status = isNameValid(addBookInfoInDataBase.authorName);
        if (!status)
        {
            printf("\n\t\t\tName contain invalid character. Please enter again.");
        }
    }
    while(!status);


    do
    {
        printf("\n\t\t\tStudent Name  = ");
        fflush(stdin);
        fgets(addBookInfoInDataBase.studentName,MAX_STUDENT_NAME,stdin);

        status = isNameValid(addBookInfoInDataBase.studentName);
        if (!status)
        {
            printf("\n\t\t\tName contain invalid character. Please enter again.");
        }
    }
    while(!status);

    do
    {
        //get date year,month and day from user
        printf("\n\t\t\tEnter date in format (day/month/year): ");
        scanf("%d/%d/%d",&addBookInfoInDataBase.bookIssueDate.dd,&addBookInfoInDataBase.bookIssueDate.mm,&addBookInfoInDataBase.bookIssueDate.yyyy);

        //check date validity
        status = isValidDate(&addBookInfoInDataBase.bookIssueDate);
        if (!status)
        {
            printf("\n\t\t\tPlease enter a valid date.\n");
        }
    }
    while(!status);

    fwrite(&addBookInfoInDataBase,sizeof(addBookInfoInDataBase), 1, fp);
    fclose(fp);

}


// search books
void searchBooks()
{
    int found = 0;
    char bookName[MAX_BOOK_NAME] = {0};
    s_BooksInfo addBookInfoInDataBase = {0};
    FILE *fp = NULL;
    int status = 0;
    fp = fopen(FILE_NAME,"rb");
    if(fp == NULL)
    {
        printf("\n\t\t\tFile is not opened\n");
        exit(1);
    }

    headMessage("SEARCH BOOKS");
    //put the control on books detail
    if (fseek(fp,FILE_HEADER_SIZE,SEEK_SET) != 0)
    {
        fclose(fp);
        printf("\n\t\t\tFacing issue while reading file\n");
        exit(1);
    }

    printf("\n\n\t\t\tEnter Book Name to search:");
    fflush(stdin);
    fgets(bookName,MAX_BOOK_NAME,stdin);

    while (fread (&addBookInfoInDataBase, sizeof(addBookInfoInDataBase), 1, fp))
    {
        if(!strcmp(addBookInfoInDataBase.bookName, bookName))
        {
            found = 1;
            break;
        }

    }

    if(found)
    {
        printf("\n\t\t\tBook id = %u\n",addBookInfoInDataBase.books_id);
        printf("\t\t\tBook name = %s",addBookInfoInDataBase.bookName);
        printf("\t\t\tBook authorName = %s",addBookInfoInDataBase.authorName);
        printf("\t\t\tBook issue date(day/month/year) =  (%d/%d/%d)",addBookInfoInDataBase.bookIssueDate.dd,
               addBookInfoInDataBase.bookIssueDate.mm, addBookInfoInDataBase.bookIssueDate.yyyy);
    }
    else
    {
        printf("\n\t\t\tNo Record");
    }

    fclose(fp);
    printf("\n\n\n\t\t\tPress any key to go to main menu.....");
    getchar();
}


// v books function
void viewBooks()
{
    int found = 0;
    char bookName[MAX_BOOK_NAME] = {0};
    s_BooksInfo addBookInfoInDataBase = {0};
    FILE *fp = NULL;
    int status = 0;
    unsigned int countBook = 1;

    headMessage("VIEW BOOKS DETAILS");
    fp = fopen(FILE_NAME,"rb");
    if(fp == NULL)
    {
        printf("File is not opened\n");
        exit(1);
    }
    if (fseek(fp,FILE_HEADER_SIZE,SEEK_SET) != 0)
    {
        fclose(fp);
        printf("Facing issue while reading file\n");
        exit(1);
    }

    while (fread (&addBookInfoInDataBase, sizeof(addBookInfoInDataBase), 1, fp))
    {
        printf("\n\t\t\tBook Count = %d\n\n",countBook);
        printf("\t\t\tBook id = %u",addBookInfoInDataBase.books_id);
        printf("\n\t\t\tBook name = %s",addBookInfoInDataBase.bookName);
        printf("\t\t\tBook authorName = %s",addBookInfoInDataBase.authorName);
        printf("\t\t\tBook issue date(day/month/year) =  (%d/%d/%d)\n\n",addBookInfoInDataBase.bookIssueDate.dd,
               addBookInfoInDataBase.bookIssueDate.mm, addBookInfoInDataBase.bookIssueDate.yyyy);
        found = 1;
        ++countBook;
    }
    fclose(fp);

    if(!found)
    {
        printf("\n\t\t\tNo Record");
    }
    printf("\n\n\t\t\tPress any key to go to main menu.....");

    fflush(stdin);
    getchar();

}

// delete function
void deleteBooks()
{
    int found = 0;
    int bookDelete = 0;
    sFileHeader fileHeaderInfo = {0};
    char bookName[MAX_BOOK_NAME] = {0};
    s_BooksInfo addBookInfoInDataBase = {0};
    FILE *fp = NULL;
    FILE *tmpFp = NULL;
    int status = 0;

    headMessage("Delete Books Details");

    fp = fopen(FILE_NAME,"rb");
    if(fp == NULL)
    {
        printf("File is not opened\n");
        exit(1);
    }

    tmpFp = fopen("tmp.bin","wb");
    if(tmpFp == NULL)
    {
        fclose(fp);
        printf("File is not opened\n");
        exit(1);
    }

    fread (&fileHeaderInfo,FILE_HEADER_SIZE, 1, fp);
    fwrite(&fileHeaderInfo,FILE_HEADER_SIZE, 1, tmpFp);


    printf("\n\t\t\tEnter Book ID NO. for delete:");
    scanf("%d",&bookDelete);


    while (fread (&addBookInfoInDataBase, sizeof(addBookInfoInDataBase), 1, fp))
    {
        if(addBookInfoInDataBase.books_id != bookDelete)
        {
            fwrite(&addBookInfoInDataBase,sizeof(addBookInfoInDataBase), 1, tmpFp);
        }
        else
        {
            found = 1;
        }
    }

    (found)? printf("\n\t\t\tRecord deleted successfully....."):printf("\n\t\t\tRecord not found");

    fclose(fp);
    fclose(tmpFp);
    remove(FILE_NAME);
    rename("tmp.bin",FILE_NAME);

}

void updateCredential(void)
{
    sFileHeader fileHeaderInfo = {0};
    FILE *fp = NULL;
    unsigned char userName[MAX_SIZE_USER_NAME] = {0};
    unsigned char password[MAX_SIZE_PASSWORD] = {0};

    headMessage("Update Credential");

    fp = fopen(FILE_NAME,"rb+");
    if(fp == NULL)
    {
        printf("File is not opened\n");
        exit(1);
    }

    fread (&fileHeaderInfo,FILE_HEADER_SIZE, 1, fp);
    if (fseek(fp,0,SEEK_SET) != 0)
    {
        fclose(fp);
        printf("\n\t\t\tFacing issue while updating password\n");
        exit(1);
    }

    printf("\n\n\t\t\tNew Username:");
    fflush(stdin);
    fgets(userName,MAX_SIZE_USER_NAME,stdin);

    printf("\n\n\t\t\tNew Password:");
    fflush(stdin);
    fgets(password,MAX_SIZE_PASSWORD,stdin);

    strncpy(fileHeaderInfo.username,userName,sizeof(userName));
    strncpy(fileHeaderInfo.password,password,sizeof(password));
    fwrite(&fileHeaderInfo,FILE_HEADER_SIZE, 1, fp);

    fclose(fp);

    printf("\n\t\t\tYour Password has been changed successfully");
    printf("\n\t\t\ttLogin Again:");
    fflush(stdin);
    getchar();
    exit(1);
}

void menu()
{
    int choice = 0;
    do
    {
        headMessage("MAIN MENU");
        printf("\n\n\n\t\t\t1.Add Books");
        printf("\n\t\t\t2.Search Books");
        printf("\n\t\t\t3.View Books");
        printf("\n\t\t\t4.Delete Book");
        printf("\n\t\t\t5.Update Password");
        printf("\n\t\t\t0.Exit");
        printf("\n\n\n\t\t\tEnter choice => ");

        scanf("%d",&choice);
        switch(choice)
        {
        case 1:
            addBookInDataBase();
            break;
        case 2:
            searchBooks();
            break;
        case 3:
            viewBooks();
            break;
        case 4:
            deleteBooks();
            break;
        case 5:
            updateCredential();
            break;
        case 0:
            printf("\n\n\n\t\t\t\tThank you!!!\n\n\n\n\n");
            exit(1);
            break;
        default:
            printf("\n\n\n\t\t\tINVALID INPUT!!! Try again...");
        }																						//Switch Ended
    }
    while(choice!=0);																				//Loop Ended
}


//login password
void login()
{
    unsigned char userName[MAX_SIZE_USER_NAME] = {0};
    unsigned char password[MAX_SIZE_PASSWORD] = {0};
    int L=0;
    sFileHeader fileHeaderInfo = {0};
    FILE *fp = NULL;

    headMessage("Login");

    fp = fopen(FILE_NAME,"rb");
    if(fp == NULL)
    {
        printf("File is not opened\n");
        exit(1);
    }

    fread (&fileHeaderInfo,FILE_HEADER_SIZE, 1, fp);

    fclose(fp);

    do
    {

        printf("\n\n\n\t\t\t\tUsername:");
        fgets(userName,MAX_SIZE_USER_NAME,stdin);

        printf("\n\t\t\t\tPassword:");
        fgets(password,MAX_SIZE_PASSWORD,stdin);

        if((!strcmp(userName,fileHeaderInfo.username)) && (!strcmp(password,fileHeaderInfo.password)))
        {
            menu();
        }
        else
        {
            printf("\t\t\t\tLogin Failed Enter Again Username & Password\n\n");
            L++;
        }
    }
    while(L<=3);
    if(L>3)
    {
        headMessage("Login Failed");
        printf("\t\t\t\tSorry,Unknown User.");
        getch();
        system("cls");
    }

}

int isFileExists(const char *path)
{
    // Try to open file
    FILE *fp = fopen(path, "rb");
    int status = 0;

    // If file does not exists
    if (fp != NULL)
    {
        status = 1;
        // File exists hence close file
        fclose(fp);
    }

    return status;
}

void init()
{
    FILE *fp = NULL;
    int status = 0;
    const char defaultUsername[] ="aticleworld\n";
    const char defaultPassword[] ="aticleworld\n";

    sFileHeader fileHeaderInfo = {0};

    status = isFileExists(FILE_NAME);

    if(!status)
    {
        //create the binary file
        fp = fopen(FILE_NAME,"wb");
        if(fp != NULL)
        {
            //Copy default password
            strncpy(fileHeaderInfo.password,defaultPassword,sizeof(defaultPassword));
            strncpy(fileHeaderInfo.username,defaultUsername,sizeof(defaultUsername));
            fwrite(&fileHeaderInfo,FILE_HEADER_SIZE, 1, fp);

            fclose(fp);
        }
    }
}



int main()
{

    init();
    welcomeMessage();
    login();

    return 0;
}

See below video to understand the working of the library management project in C:

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