c programs

2d_array_pointer.c

#include<stdio.h>
#include<stdlib.h>
void main()
{
  int a[2][3];
  int (*p)[3];
  p = a;
  int i,j,k;
  printf("Enter elements of '2 x 3' array:\n");
  for(i=0;i<2;i++)
  {
    for(j=0;j<3;j++)
      scanf("%d",(*(p+i)+j));
  }
  printf("\n\nAddresses of array is:\n");
  for(i=0;i<2;i++)
  {
    for(j=0;j<3;j++)
      printf("%p\t",(*(p+i)+j));
    printf("\n");
  }
  printf("\n\nArray is:\n");
  for(i=0;i<2;i++)
  {
    for(j=0;j<3;j++)
      printf("%d\t",*(*(p+i)+j));
    printf("\n");
  }
}

array_of_structures.c

#include<stdio.h>
#include<string.h>
struct author{
  char first[25];
  char last[25];
};
struct book{
  char title[50];
  struct author name;
  long int isbn_number;
};
void print_book(struct book *bk){
  printf("Title of the book : ");
  puts(bk -> title);
  printf("Name of the author is : ");
  printf("%s %s\n",bk -> name.first, bk -> name.last);
  printf("ISBN Number = %ld\n",bk -> isbn_number);
  printf("\n\n");
}
void input_book(struct book *bk){
  printf("Enter title of the book : ");
  scanf("%s",bk -> title);
  printf("Enter first name of the author : ");
  scanf("%s",bk -> name.first);
  printf("Enter last name of the author : ");
  scanf("%s",bk -> name.last);
  printf("Enter ISBN Number : ");
  scanf("%ld",&(bk -> isbn_number));
  printf("\n\n");
}
void main(){
  int i;
  struct book BOOK[2];
  printf("Input information on books: \n\n");
  for(i=0;i<2;i++)
  {
    input_book(BOOK + i);

  }
  printf("Books are:\n\n");
  for(i=0;i<2;i++)
  {
    print_book(BOOK + i);
  }
}

malloc.c

#include<stdio.h>
#include<stdlib.h>
void main()
{
  int* int_;
  float* float_;
  int i;
  int_ = (int*)malloc(sizeof(int));
  *int_ = 10;
  printf("%p : %d\n",int_,*int_);
  free(int_);
  printf("After deallocating the memory using free:\n");
  printf("%p : %d\n",int_,*int_);
  float_ = (float*)malloc(sizeof(float));
  *float_ = 12.4546;
  printf("\n\n%p : %f\n",float_,*float_);
  free(float_);
  printf("After deallocating the memory using free:\n");
  printf("%p : %f\n\n\n",float_,*float_);
  int_ = (int*)malloc(5*sizeof(int));
  printf("Allocating the memory for an array: \n");
  for(i=0;i<5;i++)
  {
    *(int_+i) = i+1;
    printf("%p : %d\n",int_ + i,*(int_ + i));
  }
  free(int_);
}

structure.c

#include<stdio.h>
#include<string.h>
struct book{
  char name[50];
  char author[50];
  long int isbn_number;
};
void print_book(struct book bk){
  printf("Title of the book : ");
  puts(bk.name);
  printf("Name of the author : ");
  puts(bk.author);
  printf("ISBN Number = %ld\n",bk.isbn_number);
}
void print_by_ref(char* name,char* author,long int* isbn_number){
  printf("Title of the book : ");
  puts(name);
  printf("Name of the author : ");
  puts(author);
  printf("ISBN Number = %ld\n",*isbn_number);
}
void passing_struct_pointer(struct book *bk){
  printf("Title of the book : ");
  puts(bk -> name);
  printf("Name of the author : ");
  puts(bk -> author);
  printf("ISBN Number = %ld\n",bk -> isbn_number);
}
void input_book(struct book *bk){
  printf("Enter title of the book : ");
  gets(bk -> name);
  printf("Enter name of the author : ");
  gets(bk -> author);
  printf("Enter ISBN Number : ");
  scanf("%ld",&(bk -> isbn_number));
  printf("\n\n");
}
void main(){
  struct book book_1,book_2;
  strcpy(book_1.name,"You Can Win");
  strcpy(book_1.author,"Shiv Khera");
  book_1.isbn_number = 1234567;
  printf("Printing from function (Call by value) : \n");
  print_book(book_1);
  printf("\n\n");
  printf("Printing from function (Call by reference) : \n");
  print_by_ref(book_1.name,book_1.author,&book_1.isbn_number);
  printf("\n\n");
  printf("Printing from function (Passing reference of whole structure) : \n");
  passing_struct_pointer(&book_1);
  printf("\n\n");
  printf("Enter input for book 2 (from function) : \n");
  input_book(&book_2);
  printf("Printing from function (Call by value) : \n");
  print_book(book_2);
  printf("\n\n");
}