Accepting Command Line Arguments

ACCEPTING COMMAND LINE ARGUMENTS

C facilitates its programmers to pass command arguments. Command-line arguments are given after the name of a program in command-line operating systems like DOS or Linux, and are passed in to the program from the operating system.

Till now, no arguments were passed to the main(). But now in order to understand command-line arguments, you must first understand the full declaration of the main function. The main () can accept two arguments,

• The first argument is an integer value that specifies number of command-line arguments. full lis

• The second argument is a full list of all of the command- line arguments.

The full declaration of main () can be given as

int main (int arg c, char 9c, char *argv[])

The integer, arg c specifies the number of arguments passed into the program from the command line, including the name of the program.

The array of character pointers, argv contains the list of all the arguments. argv [0] is the name of the program, or an empty string if the name is not available. argv[1] to argv [argc 1] specifies the command line argument. In the C program, every element in the argv can be used as a string. Moreover, elements of argv can also be accessed as a two-dimensional array. Note that argv [argc] is a null pointer.

In other words, each element of the array argv is a pointer where each pointer points to a string. Thus, argv [0] points to a string that contains the first parameter on the command line which is the program's name, argv[1] points to the next parameter, and so on. Look at the program given below which illustrates the use of command line arguments.

int main(int argc, char *argv[])

{

int i;

printf("\n Number of argumnets passed = %d", argc);

for (i = 0; i < argc; i++)

printf("\n arg[i] = %s", argv[i]);

return 0;

}

In the program, the main () accepts command line argu- ments through argc and argv. In the main() function, the value of argc is printed which gives the number of arguments passed. Then each argument passed is printed in the for loop using the array of pointers, argv.

For example when you execute this program from dos prompt by writing

C:\>tc clpro.c Reema Thareja

Then argc = 3, where argv [0] == clpro.c

argv[1] = Reema and argv[2] = Thareja

1. Write a program to read a file character by character, and display it simultaneously on the screen.

#include <stdio.h>

#include <string.h>

main()

{

FILE *fp;

int ch;

char filename [20];

printf("\n Enter the filename: ");

fp = fopen(filename, "r");

if (fp==NULL)

{

printf("\n Error Opening the File");

exit (1);

}

ch= fgetc (fp);

while (ch!= EOF)

{

putchar (ch);

ch = fgetc (fp);

}

fclose(fp);

}

Output

Enter the filename: Letter.TXT

Hello how are you?

2. Write a program to count the number of characters and number of lines in a file.

#include <stdio.h>

#include <string.h>

main()

{

FILE *fp;

int ch, no_of_characters= 0, no_of_lines = 1;

char filename [20];

printf("\n Enter the filename: ");

fp = fopen(filename, "r");

if (fp==NULL)

{

printf("\n Error Opening the File");

exit(1);

}

ch= fgetc (fp);

while (ch!= EOF)

{

if (ch=='\n')

no_of_lines++;

no_of_characters++;

ch = fgetc (fp);

}

if (no_of_characters > 0)

printf("\n In the file %s, there are %d lines and %d characters", filename, no_of_lines, no_of_characters);

else

printf("\n File is empty");

fclose(fp);

}

Output

Enter the filename: Letter.TXT

In the file Letter.TXT, there is 1 line and 18 characters

3. Write a program to print the text of a file on screen by printing the text line by line and displaying the line numbers before the text in each line. Use command line argument to enter the filename.

#include <stdio.h>

#include <conio.h>

int main()

{

FILE *fp1;

char text [100], ch;

int line = 1;

int i=0;

clrscr();                                                    

if (argc != 2)

{

printf("\n Full information is not provided. Please provide a filename");

 return 0;

}

fpl = fopen (argv[1], "r");

if (fpl == NULL)

{

printf("\n File Opening Error");

return 0;

}

i = 0;

while (feof (fp1)==0)

{

fscanf (fp1, "%c", &ch);

if (ch == '\n')

{

line++;

text [i]='\0';

printf("%d %s", line, text);

i=0;

}

text [i] = ch;

i++;

}

text [i] = '\0';

printf("%s", text);

getch();

return 0;

}

Output

1 Hello how are you?

4. Write a program to compare two files to check whether they are identical or not.

#include <stdio.h>

#include <conio.h>

main()

{

FILE *fp1, *fp2;

int ch1, ch2;

char filenamel [20], filename2 [20];

clrscr();

printf("\n Enter the name of the first file: ");

gets (filename1);

fflush(stdin);

printf("\n Enter the name of the second file: ");

gets (filename2);

fflush(stdin);

if ((fp1= fopen(filenamel, "r"))==0)

{

printf("\n Error opening the first file");

exit(1);

}

if ((fp2=fopen (filename2, "r"))==0)

{

printf("\n Error opening the second file");

exit(1);

}

ch1= fgetc (fpl);

ch2= fgetc (fp2);

while (ch1!= EOF && ch2 != EOF && ch1==ch2)

{

/* Reading and comparing the contents of two files */

ch1 = fgetc (fp1);

ch2 = fgetc (fp2);

}

if (ch1==ch2)

printf("\n Files are identical");

else

printf("\n Files are not identical");

fclose (fp1);

fclose (fp2);

getch();

return 0;

}

Output

Enter the name of the first filename:

Comments.TXT

Enter the name of the second filename:

Letter.TXT

Files are not identical

5. Write a program to copy one file into another. Copy one character at a time.

#include <stdio.h>

#include <conio.h>

main()

{

FILE *fpl, *fp2;

int ch;

char filename1 [20], filename2 [20];

clrscr();

printf("\n Enter the name of the first file: ");

gets (filename1);

fflush(stdin);

printf("\n Enter the name of the second file: ");

gets (filename2);

fflush(stdin);

if ((fp1=fopen(filename1, "r"))==0)

{

printf("\n Error opening the first file");

exit (1);

}

if ((fp2= fopen(filename2, "w"))==0)

{

printf("\n Error opening the second file");

exit (1);

// Copy from fpl to fp2

ch = fgetc (fp1);

while (ch!= EOF)

{

putc(ch, fp2);

ch = fgetc (fp1);

}

printf("\n FILE COPIED");

fclose(fpl);

fclose(fp2);

getch();

return 0;

}

Output

Enter the name of the first filename:

Comments.TXT

Enter the name of the second filename:

User_Comments.TXT

FILE COPIED

6. Write a program to copy one file into another. Copy multiple characters simultaneously.

#include <stdio.h>

#include <conio.h>

main ()

{

FILE *fp1, *fp2;

char filenamel [20], filename2 [20];

clrscr();

printf("\n Enter the name of the first filename: ");

gets (filename1);

fflush(stdin);

printf("\n Enter the name of the second filename: ");

gets (filename2);

fflush(stdin);

if ((fp1=fopen(filename1, "r"))==0)

{

printf("\n Error opening the first file");

exit (1);

}

if ((fp2= fopen(filename2, "w"))==0)

{

printf("\n Error opening the second file");

exit (1);

}

while ((fgets (str, sizeof(str),fp1)) != NULL) fputs (str, fp2);

fclose (fp1);

fclose (fp2);

getch();

return 0;

}

Output

Enter the name of the first filename:

Comments.TXT

Enter the name of the second filename:

User_Comments.TXT

FILE COPIED

7. Write a program to read a file that contains characters. Encrypt the data in this file while writing it into another file. (e.g., while writing the data in another file you can use the formula ch = ch-2, i.e., if the data contains character 'red' the encrypted data becomes 'pcb').

#include <stdio.h>

#include <conio.h>

int main(int argc, char *argv[])

{

FILE *fp1, *fp2;

char ch,

clrscr();

if (argc != 3)

{

printf("\n Full information is not provided");

return 0;

}

fpl = fopen (argv[1], "r");

if (fp1== NULL)

{

printf("\n File Opening Error");

return 0;

}

fp2= fopen (argv[2], "w");

if (fp2 == NULL)

{

printf("\n File Opening Error");

return 0;

}

while (feof (fp1)==0)

{

fscanf (fpl, "%c", &ch);

fprintf (fp2, "%c", ch - 2);

/*encrypted character is printed on the screen */

}

printf("\n The encrypted data is written to the file");

fclose (fp2);

fcloseall();

getch();

return 0;

}

Output

The encrypted data is written to the file

8. Write a program to read a file that contains lower case characters. Then write these characters into another file with all lower case characters converted into or upper case (e.g., if the file contains data - 'red' it must be written in another file as 'RED').

#include <stdio.h>

#include <conio.h>

int main(int argc, char *argv[])

{

FILE *fp1, *fp2;

char ch;

clrscr();

if (argc != 3)

{

printf("\n Full information is not provided");

return 0;

}

fpl = fopen (argv[1], "r");

if (fpl == NULL)

{

printf("\n File Opening Error");

return 0;

}

fp2= fopen (argv[2], "r");

if (fp2 == NULL)

{

printf("\n File Opening Error");

return 0;

}

while (feof (fp1) == 0)

{

fscanf(fp1, "%c", &ch);

fprintf (fp2, "%c", ch - 32);

}

fcloseall();

printf("\n File copied with upper case characters");

getch();

return 0;

}

Output

File copied with upper case characters

9. Write a program to merge two files into a third file. The names of the files must be entered using command line arguments.

#include <stdio.h>

#include <conio.h>

int main(int argc, char *argv[])

{

FILE *fp1, *fp2, *fp3;

char ch;

clrscr();

if (argc != 4) // Read three filenames from the user

{

printf("\n Full information is not provided");

return 0;

}

fpl = fopen (argv[1], "r");

if (fp1== NULL)

{

printf("\n File Opening Error");

return 0;

}

Fp2= fopen (argv[2], "w");

if (fp2== NULL)

{

printf("\n File Opening Error");

return 0;

}

fp3= fopen (argv[3], "w");

if (fp3== NULL)

{

printf("\n File Opening Error");

return 0;

}

while (feof (fpl) != 0)

{

fscanf (fp1, "%c", &ch);

fprintf (fp3, "%c", ch);

}

while (feof (fp2) != 0)

{

fscanf (fp2, "%c", &ch);

fprintf (fp3, "%c", ch);

}

fcloseall();

printf("\n File merged");

getch();

return 0;

}

Output

File merged

10. Write a program to read some text from the keyboard and store it in a file.

#include <stdio.h>

#include <string.h>

main()

{

FILE *fp;

char filename [20], str[100];

printf("\n Enter the filename: ");

fp = fopen(filename, "w");

if (fp==NULL)

{

printf("\n Error Opening The File");

exit(1);

}

printf("\n Enter the text: ");

gets (str);

fflush(stdin);

fprintf (fp, "%s", str);

fclose(fp);

}

Output

Enter the filename: Greet.TXT

Enter the text: Good Morning

11. Write a program to read the details of a student and then print it on the screen as well as write it into a file.

#include <stdio.h>

#include <conio.h>

int main()

{

FILE *fp;

typedef struct student

{

int roll_no;

char name [80];

float fees;

char DOB [80];

} STUDENT;

STUDENT studl;

clrscr();

fp = fopen("student_details.dat", "w");

if (fp == NULL)

{

printf("\n File Opening Error");

return 0;

}

printf("\n Enter the roll number: ");

scanf("%d", &studl.roll_no);

printf("\n Enter the name: ");

scanf("%s", studl.name);

printf("\n Enter the fees: ");

scanf("%f", &studl. fees);

printf("\n Enter the DOB: ");

scanf("%s", stud1. DOB);

// PRINT ON SCREEN

printf("\n *** STUDENT'S DETAILS *** " ) ;

printf("\n ROLL No. = %d", studl.roll_no);

printf("\n NAME = %s", studl.name);

printf("\n FEES = %f", studl.fees);

printf("\n_DOB = %s", stud1.DOB);

// WRITE TO FILE

fprintf (fp, "%d %s %f %s", studl.roll_no, studl.name, stud1. fees, stud1. DOB);

fclose(fp);

getch();

return 0;

}

Output

Enter the roll number: 01

bu Enter the name: Aman

Enter the fees: 45000

Enter the DOB: 20-9-91

*****STUDENT'S DETAILS *******

ROLL NO. = 01

NAME = Aman

FEES = 45000

DOB = 20-9-91

12. Write a program to read the details of a student from a file and then print it on the screen.

#include <stdio.h>

#include <conio.h>

int main()

{

FILE *fp;

typedef struct student

{

int roll no;

char name [80];

float fees;

char DOB [80];

} STUDENT;

STUDENT studl;

clrscr();

fp = fopen("student_details.dat", "w");

if (fp== NULL)

{

printf("\n File Opening Error");

return 0;

}

// READ FROM FILE

fscanf (fp, "%d %s %f %s", &studl.roll_no, tton studl.name, &studl.fees, stud1.DOB);

// PRINT ON SCREEN

printf("\n *** STUDENT'S DETAILS ***");

printf("\n ROLL No. = %d", studl.roll_no);

printf("\n NAME = %s", studl.name);

printf("\n FEES = %f", studl.fees);

printf("\n DOB = %s", stud1. DOB);

fclose(fp);

getch();

return 0;

}

Output

*****STUDENT'S DETAILS *******

ROLL NO. = = 01

NAME = Aman

FEES = 45000

DOB = 20-9-91

13. Write a program to read the details of student until a '-1' is entered and simultaneously write the data to a file.

#include <stdio.h>

#include <conio.h>

int main()

{

FILE *fp;

typedef struct student

{

 int roll_no;

char name [80];

float fees;

char DOB [80];

} STUDENT;

STUDENT studl;

clrscr();

fp = fopen("student_details.dat", "r");

if (fp== NULL)

{

printf("\n File Opening Error");

return 0;

}

printf("\n Enter the roll number: ");

scanf("%d", &studl.roll_no);

while (studl.roll_no != -1)2:

{

printf("\n Enter the name: ");

scanf("%s", stud1.name);

printf("\n Enter the fees: ");

scanf("%f", &stud1.fees);

printf("\n Enter the DOB: ");

scanf("%s", stud1. DOB);

fprintf (fp, "%d %s %f %s", studl.roll_no, studl.name, stud1. fees, stud1. DOB);

fflush(stdin);

printf("\n Enter the roll number: ");

scanf("%d", &studl.roll_no);

}

fclose(fp);

getch();

return 0;

}

Output

Enter the roll number: 01

Enter the name: Aman

Enter the fees: 45000

Enter the DOB: 20-9-91

Enter the roll number: 02

Enter the name: Divij

Enter the fees: 45000

Enter the DOB: 29-10-91

Enter the roll number: 03

Enter the name: Saransh

Enter the fees: 45000

Enter the DOB: 2-3-92

Enter the roll number: -1

14. Write program to read characters until a ‘*’ is entered. Simultaneously store these characters in a file.

#include <stdio.h>

#include <conio.h>

int main()

{

file *fp;

char ch;

clrscr();

fp = fopen("characters.dat", "w");

if (fp == NULL)

{

printf("\n File Opening Error");

return 0;

}

printf("\n Enter the characters: ");

scanf("%c", &ch);

while (ch != '*')

{

fprintf (fp, "%c", ch);

scanf("%c", &ch);

}

printf("\n Written to the file");

fclose (fp);

getch();

return 0;

}

Output

Enter the characters: abcdef*

Written to the file

15. Write a program to count the number of lower case, upper case, numbers, and special characters present in the contents of a file. (Assume that the file contains the following data: 1. Hello, How are you?)

#include <stdio.h>

#include <conio.h>

int main(int arg c, char *argv[])

{

FILE *fp;

int ch, upper_case = 0, lower_case = 0.

 numbers = 0, special_chars = 0;

 clrscr();

if (argc != 2)

{

printf("\n Full information is not provided");

return 0;

}

fp = fopen(argv[1], "r");

if (fp == NULL)

{

printf("\n File Opening Error");

return 0;

}

i=0;

while (feof (fp) == 0)

{

fscanf (fp, "%c", &ch);

if (ch >= 'A' && ch <= 'Z')

upper_ case++;

if (ch >= 'a' && ch <= 'z')

lower_case++;

if (ch >= '0' && ch <= '9')

numbers++;

else

special_chars++;

}

fclose (fp);

printf("\n Number of upper case characters = %d", upper_case);

printf("\n Number of lower case characters = %d", lower_case);

:\" printf("\n Number of digits = %d", numbers);

printf("\n Number of special characters = %d", special_chars);

getch();

return 0;

}

Output

Number of upper case characters = 2

Number of lower case characters = 2

Number of digits = 1

Number of special characters = 2

16. Write a program to write record of students to a file using array of structures.

#include <stdio.h>

#include <conio.h>

int main()

{

FILE *fp;

typedef struct student

{

int roll_no;

char name [80];

int marks;

} STUDENT;

STUDENT stud1 [5];

int i;

clrscr();

fp = fopen("student_details.txt", "w");

if(fp == NULL)

{

printf("\n File Opening Error");

return 0;

}

for (i= 0; i < 5;i++)

{

printf("\n Enter the roll number: ");

scanf("%d", &stud1 [i].roll_no);

printf("\n Enter the name: ");

scanf("%s", studl [i].name);

printf("\n Enter the marks: ");

scanf("%d", &stud1 [i].marks);

}

// PRINT ON SCREEN

for (i = 0; i < 5;i++)

printf("\n *** STUDENT'S DETAILS ***"' );

printf("\n ROLL NO. = %d", studl [i].roll_no);

eej printf("\n NAME = %s", stud1 [i].name);

printf("\n MARKS = %d", studi [i].marks);

// WRITE TO FILE

fprintf (fp, "%d %s %d", studl [i].roll_no, studl [i].name, stud1 [i].marks);

}

printf("\n Data Written to the file");

fclose(fp);

getch();

return 0;

}

Output

********STUDENT'S DETAILS ******

ROLL NO. = 01

NAME = Aditya

MARKS = 78

********STUDENT'S DETAILS *******

ROLL No. = 02

NAME = Goransh

MARKS = 100

********STUDENT'S DETAILS *******

ROLL No. = 03

NAME = Sarthak

MARKS = 81

Data Written to the file

17. Write a program to append a record to the student's file.

#include <stdio.h>

#include <conio.h>

int main()

{

FILE *fp;

typedef struct student

{

int roll_no;

char name [80];

int marks;

} STUDENT;

STUDENT studl;

clrscr();

fp = fopen("student_details.txt", "a");

if (fp == NULL)

{

printf("\n File Opening Error");

return 0;

}

printf("\n Enter the Roll Number =");

scanf("%d", &stud1.roll_no);

printf("\n Enter the Name =");

scanf("%s", stud1.name);

printf("\n Enter the Marks =");

scanf("%d", &stud1.marks);

fprintf("fp, "\n %d %s %d", stud1.roll_no, studl.name, studl.marks);

/* After entering the record add a -1 to the file to denote the end of records *

fprintf("fp, %d", -1);

printf("\n Data Appended");

fclose(fp);

getch();

return 0;

}

Output

Enter the Roll Number =04

Enter the Name = Sanchita

Enter the Marks = 50

Data Appended

18. Write a program to read the record of a particular student.

#include <stdio.h>

#include <conio.h>

int main()

{

FILE *fpl;

typedef struct student

{

int roll_no;

char name [80];

int marks;

} STUDENT;

STUDENT stud1;

int found =0, rno;

clrscr();

fpl fopen("student_details.txt", "r");

if (fpl == NULL)

{

printf("\n File Opening Error");

return 0;

}

printf("\n Enter the roll number of the student whose record has to be read: ");

scanf("%d", &rno);

while (1)

{

fscanf(fp1, "%d %s %d", &studl.roll_no, studl.name, &stud1. marks);

if (studl.roll_no == -1)

break;

if (studl.roll_no== rno)

{

found = 1;                                                                  

printf("\n The details of student are");

printf("%d %s %d", studl.roll_no,

stud1.name,stud1.marks);

break;

}

}

if (found==0)

printf("\n Record not found in the file");

fclose (fpl);

return 0;

}

Output

Enter the roll number of the student whose

record has to be read: 02

The details of student are 02 Goransh 100

19. Write a program to edit the record of a particular student.

#include <stdio.h>

#include <conio.h>

int main()

{

FILE *fpl, *fp2;

typedef struct student

{

int roll_no;

char name [80];

int marks;

} STUDENT;

STUDENT stud1;

int found =0, rno;

clrscr();

fpl = fopen("student_details.txt", "r");

if (fpl == NULL)         

{

printf("\n File Opening Error");

return 0;

}

fp2= fopen (argv[2], "w");

if (fp2 == NULL)

{

printf("\n File Opening Error");

return 0;

}

printf("\n Enter the roll number of the student whose record has to be modified: ");

scanf("%d", &rno);

while (1)

{

fscanf (fp1, "%d", &studl.roll_no);

if (studl.roll_no == -1)

break;

if (studl.roll_no== rno)

{

found = 1;

fscanf (fpl, "%s %d", studl.name, &studl.marks);

printf("\n The details of existing record are ");

printf("%d %s %d", studl.roll_no, stud1.name,stud1.marks);

printf("\n Enter the modified name of the student: ");

scanf("%s", studl.name);

printf("\n Enter the modified marks of the student: ");

scanf("%d", &studl.marks);

/* Write the modified record to the temporary file */

fprintf (fp2, "%d %s %d", studl.roll_no, studl.name, studl.marks);

}

else

{

/* Copy the non-matching records to the temporary file */

fscanf (fpl, "%s %d", studl.name, &studl.marks);

fprintf (fp2, "%d %s %d", studl.roll_no, studl.name, studl.marks);

}

}

fprintf (fp2, "%d", -1);

(fclose (fp1);

fclose(fp2);

if (found==0)

printf("\n The record with roll number &d was not found in the file", rno);

else

{

fpl fopen("student_details.txt", "w");

if (fpl == NULL)

{

printf("\n File Opening Error");

return 0;

}

fp2 fopen("temp.txt", "r");

if (fp2==NULL)

{

printf("\n File Opening Error");

return 0;

}

/* Copy the contents of temporary file into actual file */

fscanf (fp2, "%d", &studl.roll_no);

if (studl.roll_no==-1)

break;

fscanf (fp2, "%s %d", stud1. name, &studl.marks);

fprintf(fpl, "%d %s %d", studl.roll_no, studl.name, stud1. marks);

}

}

fclose(fpl);

fclose(fp2);

printf("\n Record Updated");

getch();

return 0;

}

Output

Enter the roll number of the student whose record has to be modified: 03

The details of exisitng record are -03 Sarthak 81

Enter the modified name of the student : Sarthak

Enter the modified marks of the student: 85 Record Updated

20. Write a program to delete the record of a particular student.

#include <stdio.h>

#include <conio.h>

int main()

{

FILE *fpl, *fp2;

typedef struct student

{

int roll_no;

char name [80];

int marks;

} STUDENT;

STUDENT studl;

int found =0, rno;

clrscr();

fpl = fopen("student_details.txt", "r");

if (fpl == NULL)

{

printf("\n File Opening Error");

return 0;

}

fp2 = fopen("temp.txt", "w");

if (fp2==NULL)

printf("\n File Opening Error");

return 0;

printf("\n Enter the roll number of the student whose record has to be deleted: ");

scanf("%d", &rno);

while (1)

{

fscanf (fpl, "%d", &studl.roll_no);

if (studl.roll_no == -1)

break;

if (studl.roll_no == rno)

{

found = 1;

fscanf (fp1, "%s %d", studl.name, &studl.marks);

}

// The matching record is not copied to temp file

else

{

// Copy the non-matching records to the temporary file

fscanf (fpl, "%s %d", studl.name, &studl.marks);

fprintf (fp2, "%d %s %d ", studl.roll_no, studl.name, studl.marks);

}

}

fprintf (fp2, "%d", -1);

fclose(fpl);

fclose(fp2);

if (found==0)

printf("\n The record with roll number &d was not found in the file", rno);

else

{

fpl fopen("student_details.txt", "w");

if (fpl == NULL)

{

printf("\n File Opening Error");

return 0;

}

 fp2 = fopen("temp.txt", "r");

if (fp2 == NULL)

{

printf("\n File Opening Error");

return 0;

}

// Copy the contents of temporary file into actual file

while (1)

{

fscanf (fp2, "%d", &studl.roll_no);

if (studl.roll_no ==-1)

break;

fscanf (fp2, "%s %d", studl.name, &studl.marks);

fprintf (fp1, "%d %s %d ", studl.roll_ no, studl.name, studl.marks);

}

}

fprintf (fpl, "%d ", -1);

fclose (fp1);

fclose (fp2);

printf("\n Record Deleted");

/* The programmer may delete the temp file which will no longer be required */ getch();

return 0;

}

Output

Enter the roll number of the student whose record has to be deleted: 01

Record Deleted

21. Write a program to store records of an employee in employee file. The data must be stored using binary file.

#include <stdio.h>

#include <conio.h>

main()

{

typedef struct employee

{

int emp_code;

char name [20];

int hra;

int da;

int ta;

};

FILE *fp;

struct employee e [5];

int i;

fp = fopen("employee.txt", "wb");

if (fp==NULL)

{

printf("\n Error opening file");

exit (1);

}

printf("\n Enter the details ");

for (i = 0; i < 5; i++)

{

printf("\n\n Enter the employee code:");

scanf("%d", &e [i].emp_code);

printf("\n\n Enter the name of the employee: ");

scanf("%s", e[i].name);

printf("\n\n Enter the HRA, DA, and TA: ");

scanf("%d %d %d", &e [i].hra, &e [i].da, &e [i].ta);

fwrite(&e [i], sizeof (e[i]), 1, fp);

}

fclose(fp);

getch();

return 0;

}

Output

Enter the employee code: 01

Enter the name of the employee: Gargi

Enter the HRA, DA and TA: 10000 2000 5000

Enter the employee code: 02

Enter the name of the employee: Nikita

Enter the HRA, DA and TA: 10000 2000 5000

22. Write a program to read the records stored in 'employee.txt' file in binary mode.

#include <stdio.h>

#include <conio.h>

main()

{

typedef struct employee

{

int emp_code;

char name [20];

int hra;

int da;

int ta;

};

FILE *fp;

struct employee e;

int i;

clrscr();

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

if (fp==NULL)

{

printf("\n Error opening file");

exit (1);

printf("\n THE DETAILS OF THE EMPLOYEES ARE ");

while (1)

{

fread (&e, sizeof (e), 1, fp);

if (feof (fp))

break;

printf("\n\n Employee Code: %d", e.emp_code);

printf("\n\n Name: %s", e.name);

printf("\n\n HRA, DA, and TA: %d %d %d", e.hra, e.da, e.ta);

}

fclose(fp);

getch();

return 0;

Output

Employee Code: 01

Name: Gargi

HRA, DA and TA: 10000 5000 2000

Employee Code: 02

Name: Nikita

HRA, DA and TA: 10000 5000 2000

23. Write a program to append a record in the employee file (binary file).

#include <stdio.h>

#include <conio.h>

main()

{

typedef struct employee

{

int emp_code;

char name [20];

int hra;

int da;

int ta;

};

FILE *fp;

struct employee e;

int i;

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

if (fp==NULL)

{

printf("\n Error opening file");

exit(1);

}

printf("\n\n Enter the employee code: ");

scanf("%d", &e.emp_code);

printf("\n\n Enter the name of employee: ");

scanf("%s", e.name);

printf("\n\n Enter the HRA, DA, and TA: ");

scanf("%d %d %d", &e.hra, &e.da, &e.ta);

fwrite(&e, sizeof (e), 1, fp);

fclose (fp);

printf("\n Record Appended");

getch();

return 0;

}

Output

Enter the employee code: 06

Enter the name of employee: Tanya

Enter the HRA, DA and TA: 20000 10000 3000

24. Write a program to edit the employee record stored in a binary file.

#include <stdio.h>

#include <conio.h>

main ()

{

typedef struct employee

{

int emp_code;

char name [20];

int hra;

int da;

int ta;

};

FILE *fp1, *fp2;

struct employee e;

slo abint i, ec, found = 0;

clrscr();

fp1 = fopen("employee.txt", "rb");

if (fpl==NULL)

{

printf("\n Error opening file");

exit(1);

}

fp2 = fopen("temp_emp.txt", "wb");

if (fp2==NULL)

{

printf("\n Error opening file");

exit (1);

}

printf("\n Enter the code of the employee whose information has to be edited: ");

scanf("%d", &ec);

while (1)

{

fread (&e, sizeof (e),1,fpl);

if (feof (fp1))

break;

if (e.emp_code==ec)

{

found=1;

printf("\n The existing record is: %d %s %d %d %d", e.emp_code, e.name, e.hra, e.ta, e.da);

printf("\n Enter the modified name: ");

scanf("%s", e.name);

printf("\n Enter the modified HRA, TA, and DA: ");

scanf("%d %d %d", &e.hra, &e.ta, &e.da);

fwrite(&e, sizeof (e), 1, fp2);

}

else

fwrite(&e, sizeof (e),1,fp2);

}

fclose(fpl);

fclose(fp2);

if (found==0)

printf("\n Record not found"); 

else

{

fpl = fopen("employee.txt", "wb");

if (fp1==NULL)

{

printf("\n Error opening file");

exit(1);

}

fp2 = fopen("temp_emp.txt", "rb");

if (fp2==NULL)

{

printf("\n Error opening file");

exit(1);

}

while (1)

{

fread (&e, sizeof (e), 1, fp2);

if (feof (fp2))

break;

fwrite(&e, sizeof (e), 1, fpl);

}

}

fclose (fpl);

fclose(fp2);

printf("\n Record Edited");

getch();

return 0;

}

Output

Enter the code of the employee whose information has to be edited: 01

The existing record is: 01 Gargi 10000 5000 2000

Enter the modified name: Gargi

Enter the modified HRA, TA, and DA: 20000 10000 30000

Record Edited