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

// Structure to represent a book
struct books{
    int id;
    char bookName[50];
    char authorName[50];
    char date[12];
}b;

// Structure to represent a borrower
struct student{
    int id;
    char sName[50];
    char sClass[50];
    int sRoll;
    char bookName[50];
    char date[12];
}s;

FILE *fp;
// Function prototypes
void addBook();
void booksList();
void del();
void issueBook();
void issueList();
void returnBook();
void searchBook();

// Function to display the menu
int main(){

    int ch;

    while(1){
        system("cls");
        printf("Library Management System\n\n");
        printf("1.Add Book\n");
        printf("2.Books List\n");
        printf("3.Remove Book\n");
        printf("4.Issue Book\n");
        printf("5.Issued Book List\n");
        printf("6.Return Book\n");
        printf("7.Search Book\n");
        printf("0.Exit\n\n");
        printf("Enter your choice: ");
        scanf("%d", &ch);

        switch(ch){
        case 0:
            exit(0);

        case 1:
            addBook();
            break;

        case 2:
            booksList();
            break;

        case 3:
            del();
            break;

        case 4:
            issueBook();
            break;

        case 5:
            issueList();
            break;

        case 6:
            returnBook();
            break;

        case 7:
            searchBook();
            break;

        default:
            printf("Invalid Choice...\n\n");

        }
        printf("\nPress Any Key To Continue...");
        getc();
    }

    return 0;
}

// Function to add a book to the library
void addBook(){
    char myDate[12];
    time_t t = time(NULL);
    struct tm tm = *localtime(&t);
    sprintf(myDate, "%02d/%02d/%d", tm.tm_mday, tm.tm_mon+1, tm.tm_year + 1900);
    strcpy(b.date, myDate);

    fp = fopen("books.txt", "ab");

    printf("Enter book id: ");
    scanf("%d", &b.id);

    printf("Enter book name: ");
    fflush(stdin);
    fgets(b.bookName);

    printf("Enter author name: ");
    fflush(stdin);
    gets(b.authorName);

    printf("Book Added Successfully");

    fwrite(&b, sizeof(b), 1, fp);
    fclose(fp);
}


// Function to display all books in the library
void booksList(){

    system("cls");
    printf("Available Books\n\n");
    printf("%-10s %-30s %-20s %s\n\n", "Book id", "Book Name", "Author", "Date");

    fp = fopen("books.txt", "rb");
    while(fread(&b, sizeof(b), 1, fp) == 1){
        printf("%-10d %-30s %-20s %s\n", b.id, b.bookName, b.authorName, b.date);
    }

    fclose(fp);
}
// Function to remove a book from the library
   void del() {
    int id, f = 0;
    system("cls");
    printf("Remove Books\n\n");
    printf("Enter Book id to remove: ");
    scanf("%d", &id);

    FILE *ft;

    fp = fopen("books.txt", "rb");
    ft = fopen("temp.txt", "wb");

    while (fread(&b, sizeof(b), 1, fp) == 1) {
        if (id == b.id) {
            f = 1;
        } else {
            fwrite(&b, sizeof(b), 1, ft);
        }
    }

    if (f == 1) {
        printf("\n\nDeleted Successfully.");
    } else {
        printf("\n\nRecord Not Found !");
    }

    fclose(fp);
    fclose(ft);

    remove("books.txt");
    rename("temp.txt", "books.txt");
}
// Function to display issue book
void issueBook(){

    char myDate[12];
    time_t t = time(NULL);
    struct tm tm = *localtime(&t);
    sprintf(myDate, "%02d/%02d/%d", tm.tm_mday, tm.tm_mon+1, tm.tm_year + 1900);
    strcpy(s.date, myDate);

    int f=0;

    system("cls");
    printf("Issue Books\n\n");

    printf("Enter Book id to issue: ");
    scanf("%d", &s.id);

    fp = fopen("books.txt", "rb");

    while(fread(&b, sizeof(b), 1, fp) == 1){
        if(b.id == s.id){
            strcpy(s.bookName, b.bookName);
            f=1;
            break;
        }
    }

    if(f==0){
        printf("No book found with this id\n");
        printf("Please try again...\n\n");
        return;
    }

    fp = fopen("issue.txt", "ab");

    printf("Enter Student Name: ");
    fflush(stdin);
    gets(s.sName);

    printf("Enter Student Class: ");
    fflush(stdin);
    gets(s.sClass);

    printf("Enter Student Roll: ");
    scanf("%d", &s.sRoll);

    printf("Book Issued Successfully\n\n");

    fwrite(&s, sizeof(s), 1, fp);
    fclose(fp);
}

// Function to display issue list
void issueList(){
    system("cls");
    printf("Book Issue List\n\n");

    printf("%-10s %-30s %-20s %-10s %-30s %s\n\n", "S.id", "Name", "Class", "Roll", "Book Name", "Date");

    fp = fopen("issue.txt", "rb");
    while(fread(&s, sizeof(s), 1, fp) == 1){
        printf("%-10d %-30s %-20s %-10d %-30s %s\n", s.id, s.sName, s.sClass, s.sRoll, s.bookName, s.date);
    }

    fclose(fp);
}

// Function to return a book
void returnBook() {
    int id, f = 0;
    system("cls");
    printf("Return Books\n\n");
    printf("Enter Book id to return: ");
    scanf("%d", &id);

    FILE *ft;

    fp = fopen("issue.txt", "rb");
    ft = fopen("temp_issue.txt", "wb");

    while (fread(&s, sizeof(s), 1, fp) == 1) {
        if (id == s.id) {
            f = 1;
            printf("\n\nBook Returned Successfully.");
        } else {
            fwrite(&s, sizeof(s), 1, ft);
        }
    }

    if (f == 0) {
        printf("\n\nBook ID Not Found !");
    }

    fclose(fp);
    fclose(ft);

    remove("issue.txt");
    rename("temp_issue.txt", "issue.txt");
}

// Function to search book
void searchBook() {
    int id, found = 0;

    printf("Enter Book id to search: ");
    scanf("%d", &id);

    fp = fopen("books.txt", "rb");

    while (fread(&b, sizeof(b), 1, fp) == 1) {
        if (id == b.id) {
            found = 1;
            printf("\nBook Found:\n");
            printf("Book ID: %d\nBook Name: %s\nAuthor: %s\nDate: %s\n", b.id, b.bookName, b.authorName, b.date);
            break;
        }
    }

    fclose(fp);

    if (!found) {
        printf("\nBook not found with ID: %d\n", id);
    }
}

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Read inputs from stdin

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#include <stdio.h>
int main()
{
    char name[50];
    printf("Enter name:");
    scanf("%s", name);
    printf("Hello %s \n" , name );
    return 0;
    
}

About C

C language is one of the most popular general-purpose programming language developed by Dennis Ritchie at Bell laboratories for UNIX operating system. The initial release of C Language was in the year 1972. Most of the desktop operating systems are written in C Language.

Key features:

  • Structured Programming
  • Popular system programming language
  • UNIX, MySQL and Oracle are completely written in C.
  • Supports variety of platforms
  • Efficient and also handle low-level activities.
  • As fast as assembly language and hence used as system development language.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition if-else is used.

if(conditional-expression) {
   // code
} else {
   // code
}

You can also use if-else for nested Ifs and if-else-if ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to if-else-if ladder.

switch(conditional-expression) {    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
...    
    
default:     
 // code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  // code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while(condition) {  
 // code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {
  // code 
} while (condition);

Arrays

Array is a collection of similar data which is stored in continuous memory addresses. Array values can be fetched using index. Index starts from 0 to size-1.

Syntax

One dimentional Array:

data-type array-name[size];

Two dimensional array:

data-type array-name[size][size];

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity.

Two types of functions are present in C

  1. Library Functions:

Library functions are the in-built functions which are declared in header files like printf(),scanf(),puts(),gets() etc.,

  1. User defined functions:

User defined functions are the ones which are written by the programmer based on the requirement.

How to declare a Function

return_type function_name(parameters);

How to call a Function

function_name (parameters)

How to define a Function

return_type function_name(parameters) {  
  //code
}