Difference between Binary mode and Text Mode in C programming

There are mainly three difference between binary and text mode. They are as follow.

              i.      In text mode, a special character EOF whose ASCII value is 26 is inserted after the last character in the file to mark the end of file. But, there is no such special character present in the binary mode. The binary mode files keep track of the end of file from the number of characters present in the directory entry of the file.

            ii.      In text mode of file, text and numbers are stored as one character per byte. For example, the number 1234 occupies two bytes in memory but it occupies 4 bytes (one byte per character) in the file. But, in binary mode, the number occupies the number of bytes as it occupies in the memory. Thus,  the above number occupies two bytes in file also in the case of binary mode.

          iii.      In text mode, a new line character is converted into the carriage return-linefeed combination before being written to the disk. Likewise, the carriage return-line feed combination on the disk is converted into a new line when the file is read by a C program. However, these conversions doesn’t take place in the case of binary mode.

An example for binary mode of file:

Write a C program to write some text “Welcome to Acme College” to a data file in binary mode. Read its content and display it.

void main()

  {

  FILE *fptr;

  char c;

  clrscr();

  fptr=fopen("test.txt","w+b");

  if(fptr==NULL)

     {

     printf("\nFile can not be created");

     }

    fputs("Welcome to Acme College",fptr);

    rewind(fptr);

    printf("\From File\n");

    while(!feof(fptr))

      {

      printf("%c",getc(fptr));

      }

    fclose(fptr);

  getch();

  }

Example of writing structure elements to a file,

Write a C program to create a structure named book having elements name, page and price. Enter the members from keyboard. Write these data to a file.

1) Using fprintf() function

void main()

{

FILE *fp;

struct book

  {

  char name[20];

  int page;

  float price;

  };

struct book b;

fp=open("stTest.txt","wb");

if(fp==NULL)

  {

  printf("\nError");

  exit();

  }

printf("\nEnter name of book\n");

gets(b.name);

printf("\nEnter number of pages\n");

scanf("%d",&b.page);

printf("\nEnter price of book\n");

b.price=89;

fprintf(fp,"%s%d%f",b.name,b.page,b.price);

printf("\nThe file has been createed\n");

fclose(fp);

}

2. Using fwrite() function:

void main()

    {

  ….

 ……………………….

 …………….

fwrite(&b, sizeof(b),1,fp); /* 1 means one structure*/

fclose(fp);

      }

Syntax for fwrite() and fread()

fwrite(&str_variable, sizeof(str_variable), number_of_structure, file_ptr);

fread(&str_variable, sizeof(str_variable), number_of_structure, file_ptr);