How to parse a file using C?

Question

1.00/5 (2 votes)

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Here is the file sample.

########################################### Configuration File for Employee Information ##########################
#################################
  ID = 101
  Name = Anjum ####### She works for Innobox 
  sal= 30000# per month
  Experience = 5.4 
#################
ID = 102
  Name = Satya      ####### He works for Innobox 
  sal= 60000# per month
  Experience = 7.4 
####################




	ID = 103
  Name =     Ramana ####### 
  sal= 70000# per month
  Experience = 8.4
####################


	ID = 104
  Name = Trinadh ####### ## He works for Innobox
  sal     =        60000# per month
  Experience = 7.0
######################

i need to parse it and store all data in a structure. and print.

structure members are-
1.ID
2.name
3.salary
4.experience

Any claue?

Posted 28-Oct-14 9:40am

XSCHB_000

Updated 28-Oct-14 11:33am

Maciej Los

v4

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Comments

OriginalGriff 28-Oct-14 15:46pm

And?
What have you tried?
Where are you stuck?
What help do you need?

XSCHB_000 28-Oct-14 16:18pm

I am required to create a parser for parsing this file format. After parsing the input file and creating records, I am required to implement querying on these records.

I need to display the output based on the command line option.
options you can have are "-a" to display all records.
"-i number" to display a record of specific id.

code what i wrote:

#include
#include
#include
#include
#include

#define EMPLOYE_FILE_NAME "/home/supratik/Empconfig.txt"
#define ID_PARSE_DELIMITER "ID"
#define NAME_PARSE_DELIMITER "Name"
#define SALARY_PARSE_DELIMITER "sal"
#define EXPERIENCE_PARSE_DELIMITER "Experience"
#define MAX_STR_SIZE 1024
#define MAX_ID_LENGTH 3
#define MAX_NAME_LENGTH 8
#define MAX_SALARY_LENGTH 6
#define MAX_EXPERIENCE_LENGTH 5

#define MAX_LINE_READ 100

#define MAX_EMPLOYEE_RECORD 4

//static int parse_string( char *buffer );
static int Parse_file( void );
static int parse_ID( char *buffer );
static int parse_Name( char *buffer );
static int parse_Exp( char *buff);
static int parse_salary( char *buff);
static void Read_file_for_ID( FILE *fp,char *str);
static void Read_file_for_Name( FILE *fp,char *str);
static void Read_file_for_Salary( FILE *fp,char *str);
static void Read_file_for_Experience( FILE *fp,char *str);

//employee structure

struct employee
{
int id; //ID of employee
char name[30]; //Name of employee
int sal; // Salary of employee
float exp; //Experience of employee
};

struct employee record[ MAX_EMPLOYEE_RECORD -1 ];
int record_index = 0 ;

void print_record()
{
printf("Here are all records\n");
for(; record_index <=MAX_EMPLOYEE_RECORD-1; record_index++)
{
printf("ID of employee=%d\t",record[record_index].id);
printf("NAME of employee=%s\t",record[record_index].name);
printf("Salary of employee=%d\t",record[record_index].sal);
printf("experience of employee=%.1f\n",record[record_index].exp);
}
return;
}

void print_individual_record(int index)
{
printf("Here are the record\n");
printf("ID of employee=%d\t",record[index-1].id);
printf("NAME of employee=%s\t",record[index-1].name);
printf("Salary of employee=%d\t",record[index-1].sal);
printf("experience of employee=%.1f\n",record[index-1].exp);
return;
}

int main(int argc, char *argv)
{
int rc;
int value;
opterr = 0;
int index;

if(argc < 2){
printf("%s():[%d]:Invalid command, need to give more argument\n",__func__,__LINE__);
return -1;
}
while( 1)
{
//printf("We are Here\n");
static struct option long_options[] =
{
/* These options don’t set a flag.
We distinguish them by their indices. */
{"index", required_argument, 0, 'i'},
{"display", no_argument, 0, 'a'},
{0, 0, 0, 0}
};
/* getopt_long stores the option index here. */
int option_index = 0;
value = getopt_long (argc, argv, "ai:",
long_options, &option_index);
/* Detect the end of the options. */
if (value == -1)
break;
// printf("%d we are here\n",__LINE__);
switch (value)
{
case 'a':
// printf ("option -a\n");
rc = Parse_file();
if(!rc){
print_record();
}
break;

case 'i':
// printf ("option -d with value `%s'\n", optarg);
index = atoi(optarg);
// printf("%d\n",index);
rc = Parse_file();
if(!rc){
print_individual_record(index);
}
break;
default:
printf("%s():[%d]: OOPS!!bad argument, please enter valid argument\t -a\n",__func__,__LINE__);
}
}

}

static void Read_file_for_ID( FILE *fp, char *str)
{
char temp_str[ MAX_STR_SIZE ];
int line_num = 0;

memset(temp_str, 0, sizeof(temp_str));
while ((fgets(temp_str,1024,fp))!= NULL)
{
if((strstr(temp_str,str)) != NULL){
// printf("A match found on line: %d\n", line_num);
// printf("%s():%d: DEBUG: string is:%s\n",__func__,__LINE__,temp_str);
// record_index++;
parse_ID( temp_str );
}
line_num++;
}
return;
}

static void Read_file_for_Name( FILE *fp, char *str)
{
char temp_str[MAX_STR_SIZE];
int line_num = 0;
memset( temp_str, 0 , sizeof(temp_str));
while ((fgets(temp_str,1024,fp))!= NULL)
{
if((strstr(temp_str,str)) != NULL){
// printf("A match found on line: %d\n", line_num);
// printf("%s():%d: DEBUG: string is:%s\n",__fu

Sergey Alexandrovich Kryukov 28-Oct-14 15:47pm

Please stop re-posting it, better write a proper question. I already saw this "question".
The question is unclear. Just one example is not the description of input format, set aside output (parse to what?)
What do you mean "how"? By doing appropriate software development work.
What have you tried so far?
—SA

XSCHB_000 28-Oct-14 16:17pm

I am required to create a parser for parsing this file format. After parsing the input file and creating records, I am required to implement querying on these records.

I need to display the output based on the command line option.
options you can have are "-a" to display all records.
"-i number" to display a record of specific id.

code what i wrote:

#include
#include
#include
#include
#include

#define EMPLOYE_FILE_NAME "/home/supratik/Empconfig.txt"
#define ID_PARSE_DELIMITER "ID"
#define NAME_PARSE_DELIMITER "Name"
#define SALARY_PARSE_DELIMITER "sal"
#define EXPERIENCE_PARSE_DELIMITER "Experience"
#define MAX_STR_SIZE 1024
#define MAX_ID_LENGTH 3
#define MAX_NAME_LENGTH 8
#define MAX_SALARY_LENGTH 6
#define MAX_EXPERIENCE_LENGTH 5

#define MAX_LINE_READ 100

#define MAX_EMPLOYEE_RECORD 4

//static int parse_string( char *buffer );
static int Parse_file( void );
static int parse_ID( char *buffer );
static int parse_Name( char *buffer );
static int parse_Exp( char *buff);
static int parse_salary( char *buff);
static void Read_file_for_ID( FILE *fp,char *str);
static void Read_file_for_Name( FILE *fp,char *str);
static void Read_file_for_Salary( FILE *fp,char *str);
static void Read_file_for_Experience( FILE *fp,char *str);

//employee structure

struct employee
{
int id; //ID of employee
char name[30]; //Name of employee
int sal; // Salary of employee
float exp; //Experience of employee
};

struct employee record[ MAX_EMPLOYEE_RECORD -1 ];
int record_index = 0 ;

void print_record()
{
printf("Here are all records\n");
for(; record_index <=MAX_EMPLOYEE_RECORD-1; record_index++)
{
printf("ID of employee=%d\t",record[record_index].id);
printf("NAME of employee=%s\t",record[record_index].name);
printf("Salary of employee=%d\t",record[record_index].sal);
printf("experience of employee=%.1f\n",record[record_index].exp);
}
return;
}

void print_individual_record(int index)
{
printf("Here are the record\n");
printf("ID of employee=%d\t",record[index-1].id);
printf("NAME of employee=%s\t",record[index-1].name);
printf("Salary of employee=%d\t",record[index-1].sal);
printf("experience of employee=%.1f\n",record[index-1].exp);
return;
}

int main(int argc, char *argv)
{
int rc;
int value;
opterr = 0;
int index;

if(argc < 2){
printf("%s():[%d]:Invalid command, need to give more argument\n",__func__,__LINE__);
return -1;
}
while( 1)
{
//printf("We are Here\n");
static struct option long_options[] =
{
/* These options don’t set a flag.
We distinguish them by their indices. */
{"index", required_argument, 0, 'i'},
{"display", no_argument, 0, 'a'},
{0, 0, 0, 0}
};
/* getopt_long stores the option index here. */
int option_index = 0;
value = getopt_long (argc, argv, "ai:",
long_options, &option_index);
/* Detect the end of the options. */
if (value == -1)
break;
// printf("%d we are here\n",__LINE__);
switch (value)
{
case 'a':
// printf ("option -a\n");
rc = Parse_file();
if(!rc){
print_record();
}
break;

case 'i':
// printf ("option -d with value `%s'\n", optarg);
index = atoi(optarg);
// printf("%d\n",index);
rc = Parse_file();
if(!rc){
print_individual_record(index);
}
break;
default:
printf("%s():[%d]: OOPS!!bad argument, please enter valid argument\t -a\n",__func__,__LINE__);
}
}

}

static void Read_file_for_ID( FILE *fp, char *str)
{
char temp_str[ MAX_STR_SIZE ];
int line_num = 0;

memset(temp_str, 0, sizeof(temp_str));
while ((fgets(temp_str,1024,fp))!= NULL)
{
if((strstr(temp_str,str)) != NULL){
// printf("A match found on line: %d\n", line_num);
// printf("%s():%d: DEBUG: string is:%s\n",__func__,__LINE__,temp_str);
// record_index++;
parse_ID( temp_str );
}
line_num++;
}
return;
}

static void Read_file_for_Name( FILE *fp, char *str)
{
char temp_str[MAX_STR_SIZE];
int line_num = 0;
memset( temp_str, 0 , sizeof(temp_str));
while ((fgets(temp_str,1024,fp))!= NULL)
{
if((strstr(temp_str,str)) != NULL){
// printf("A match found on line: %d\n", line_num);
// printf("%s():%d: DEBUG: string is:%s\n",__fu

PIEBALDconsult 28-Oct-14 15:53pm

There's a decent change that a Regular Expression can do most of that.

XSCHB_000 28-Oct-14 16:05pm

could you explain , I am not getting

[no name] 28-Oct-14 16:42pm

Also this should give you an idea:
a.) Reading line by line
b.) Delete for each line from first occurence of "#" to the end of line
c.) Evaluate remaining "a = b"

But most probably you will find some "lib" because it is looking very unix style.

2 solutions

Solution 2

No I don't like to dive trough all the code in your comment.

But this should give you a first idea:
a.) Read line by line
b.) Delete for each line from first occurence of "#" to the end of line, becuase "#" seems to start comment.
c.) In case remaing line is not empty and contains a "=" then evaluate remaining "a = b"

Not a solution which can be used imediatelly, but maybe some hints about the logic.

See solution #3 for implementation hints.

Posted 28-Oct-14 11:32am

User 11060979

Updated 28-Oct-14 13:27pm

v3

Comments

Maciej Los 28-Oct-14 17:37pm

Very good tutorial ;)
+5!

[no name] 28-Oct-14 17:39pm

Really not kidding? If no then thank you Maciej! Regards, Bruno

Maciej Los 28-Oct-14 17:41pm

Check the Reputation to find out i'm kidding or not ;)
Cheers,
Maciej

[no name] 28-Oct-14 17:51pm

Thanks, Bruno

Andreas Gieriet 28-Oct-14 19:20pm

My 5!
Cheers
Andi

[no name] 28-Oct-14 19:24pm

Thank you Andy. Will give a link in my answer how to do it. Regards, Bruno

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Andreas Gieriet · Accepted Answer · 2014-10-28T13:19:00

Solution 3

Your language might be defined in "pseudo" EBNF like

txt

File       = { Skip } { Record } .
Record     = Field<ID> Field<Name> Field<Sal> Field<Experience> .
Field<Key> = { WS } Key { WS } "=" { WS } Text { Skip } .
Skip       = { WS } [HASH { ANY-CHAR-EXCEPT-NL } ] NL .
Text       = ANY-CHAR-EXCEPT-HASH-WS { ANY-CHAR-EXCEPT-HASH-WS } .

Follow the steps as decribed by Bruno Sprecher in Solution #2.
You might use the C-functions

strcspn
strtok
strncpy

Cheers
Andi

Posted 28-Oct-14 13:19pm

Andreas Gieriet

Comments

[no name] 28-Oct-14 19:28pm

My 5 and a link to your solution and a sorry for And"y" instead of Andi. Regards, Bruno

Andreas Gieriet 29-Oct-14 12:18pm

Thanks for your 5!
Cheers
Andi
PS: No problem with the "wrong" naming ;-)

Sergey Alexandrovich Kryukov 29-Oct-14 0:08am

5ed. Well, "pseudo" EBNF is a bit too much. :-) There is no "E" in this kind of BNF. Not sure OP can understand it...
—SA

Andreas Gieriet 29-Oct-14 12:22pm

Thanks for your 5, Sergey!
"pseudo" due to the "generic" production (Field<key>).
*E*BNF since to my understanding, repetitions ({ ... }) do not exist on BNF - they are only available as recursion in BNF.
Cheers
Andi

Sergey Alexandrovich Kryukov 29-Oct-14 13:46pm

Well, maybe. It's that my impression was more like pseudo-BNF. You made it up, anyway. :-)
Thank you.
—SA

Maciej Los 29-Oct-14 2:28am

+5!

Andreas Gieriet 29-Oct-14 12:18pm

Thanks for your 5!
Cheers
Andi