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Closing Files: During a write to a file, the data written is not put on the disk immediately. It is stored in a buffer. When the buffer is full, all its contents are actually written to the disk. The process of emptying the buffer by writing its contents to disk is called flushing the buffer. Losing the file flushes the buffer and releases the space taken by the FILE structure which is returned by fopen. For this fclose () function is used.

Syntax:

fclose (File * stream (s);

Correct option is (a) EOF

printf ( ) → This function writes formatted data to screen. This function allows to supply the input in a fixed format and to obtain the output in the specified form. The printf () function interprets the contents of the format string.

Syntax:

Printf (“formatted string”, variables); if needed
Example 1.
Printf (“Average = % d percentage = % of’, avg. per);
Here the %d and %f are conversion characters.
They tell printf () to print the value of avg as an integer and per as afloat.

getchar ( ): Using this function any single ASCII character can be inputted in any char type of a variable. This function is available in stdio.h header file so it must be included in the program, in the beginning, using # include declarative.
For example,

#include<stdio.h>
#include<conio.h>
void main ()
{
char x;
x = getchar();
cout << “you entered” << x;
}

Random data file

If the given stream has buffered output, fflush writes the output for a stream to the associated file.

fclose() statement

SEEK SET file pointer position of seeking function seeks from the beginning.

fread() statement is used to read the data from a file.

‘w’ mode (for writing)

fread( ): This function reads a specified number of equalsized data items from an input stream into a block, fread returns the number of items (not bytes) actually read on success.

Syntax:

fread (& name_of_structure, size_of_(structure name), l, file pointer); e.g.,

struct employee
{
char nm[20]; /* 20 bytes */
int age; /* 2 bytes */
};
struct employee Emp;
fread (&Emp, size of (Emp), 1, fp);

Here, the fread function can read 22 bytes of information from the file pointed by file pointer fp. fwrite( ): This function appends a specified number of equal-sized data items to an output file.

Syntax:

fwrite (& struct—name, size of (struct), 1, fp); e.g.,

street address
{
char city [30]; /* 30 bytes */
long in pin; /* 2 bytes */
char country [20]; /* 20 bytes */
};
struct address add;
FILE *fp;
fwrite (& add, size of (add), 1, fp);

File Opening Modes: The tasks performed by fopen() when a file is opened in each of these modes are also mentioned. Character Used

for Mode → Meaning

w → Create for write

r → Open for reading

a → Open for append/create a new file

w+ → Create for read/write

r+ → Open for read/write

a+ → Open for read/write/create new file

Program:

#include<stdio.h>
#include<conio.h>
void main()
{
FILE *fsrc, *ftgt;
char ch;
clrscr();
fsrc = fopen(“tiyl.c”, “r”);
if (fs = = NULL)
{
puts (“Cannot open source file”);
exit();
}
ftgt = fopen(“tiy2.c”, “w”);
if (ft = = NULL)
{
puts (“Cannot open target file”);
fclose(fs);
exit();
} .
while(1)
{ . ch = fgetc(fsrc);
if (ch = = EOF)
break;
else
fputc(ch, ftgt);
}
fclose(fsrc);
fclose(ftgt);
}

Correct option is (a) fseek ()

Correct option is (b) fgets ()

Correct option is (b) END

Reading from files: To read from a file, ‘C’ provides the following functions:

To read data from file, it should exist.

fscanf (): This function is used to read data from a file. It is very similar to scanf () function. It scans a series of input fields (one at a time).

Syntax:

fscanf () file * stream, “format specifiers” , “Variables”).