How to copy part of text file into a string in C? - c

Question

I have a text file with:
recipName=Fork friend=Cup sonName=Spork feature=hair sendName=Spoon"
What I want to do is copy all the words before an = sign to one character array, and copy the stuff to the right of the = to another character array or string.
This is my code so far:
int main (int argc, char * argv[])
{
char data[100];
char line[5][100];
char key[5][100];
char value[5][100];
FILE * fdata = fopen(argv[1], "r"); //read data.txt file
FILE * ftemp = fopen(argv[2], "r"); //read and write to template.txt file
if (fdata == NULL)
{
printf("could not read file.\n");
}
int i = 0;
while (fgets(data, 100, fdata) != NULL)
{
printf("data: %s", data);
//this is where i get stuck, idk how to utilize this loop to copy the variable and variable names from the data.txt file i was given...thanks for the help
++i;
}
fclose(fdata);
fclose(ftemp);
return 0;
}

Answer 1

there might be some better functions that will do more of what you want in string.h
you will have to work out the logistics and count the number of '=' characters and decide how to handle that.
#include <string.h>
char *ptr1, *ptr2;
char tempstring[100];
char before[100];
char after[100];
/* you already have data[] filled... where you get stuck */
ptr1 = strchr( data, '=' ); /* find first occurence of = */
ptr2 = strrchr( data, '=' ); /* find last occurence of = */
if ( *ptr1 == '\0' )
{
/* did not find '=' print error message and stop */
}
if ( *ptr2 == '\0' )
{
/* did not find '=' print error message and stop */
}
/* below is what you are interested in */
strcpy( tempstr, data );
ptr1 = strchr( tempstr, '=' );
*ptr1 = '\0'; /* turn = into null */
strcpy( before, tempstr );
printf("everything before = character is %s\n", tempstr ); /* watch out if = is first character, nothing before it */
strcpy( tempstr, data );
ptr2 = strchr( tempstr, '=' );
ptr2++;
if ( *ptr2 != '\0' ) /* = might have been last character */
{
strcpy( after, tempstr );
printf("everything after = character is %s\n", tempstr );
}
so for the first strchr call,
before[] will have "recipName"
and after[] will have "Fork friend=Cup sonName=Spork feature=hair sendName=Spoon"
you can do a
sscanf( after, "%s", after2 );
to get just "Fork" into after2[] array assuming there will always be a space character separating things.

Answer 2

for chqrlie
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
# define MAX 5
int Count_Token ( char str[], char token )
{
char *p;
int cnt = 0;
/* str must be null terminated with '\0' otherwise infinite loop will happen */
p = str;
while ( *p != '\0' )
{
if ( *p == token )
cnt++;
p++;
}
return cnt;
}
void Get_KeyValue_at_Position( char str[], char token, int position, char k[], char v[] )
{
char *ptr;
char temp_str[100];
int i;
ptr = str;
/* assumes str[] passed in does not have leading space before first key */
/* this for loop puts ptr on start of key at position */
for ( i = 0; i < position; i++ }
{
/* move ptr to next space */
while (( *ptr != ' ' ) && ( *ptr != '\0' ))
ptr++;
/* account for more than one space separating key/value pairs and put ptr on beginning of next key */
while ( *ptr == ' ' )
ptr++;
}
/* get key */
strcpy( temp_str, ptr )
ptr_token = strchr( temp_str, token );
*ptr_token = '\0';
strcpy( k, tempstr );
/* get value */
strcpy( temp_str, ptr );
ptr_token = strchr( temp_str, token );
ptr_token++;
strcpy( v, ptr_token );
}
int main ( int argc, char * argv[] )
{
char data[100];
char key[MAX][100]; /* has string before token */
char value[MAX][100]; /* has string afte token */
FILE *fdata;
fdata = fopen(argv[1], "r"); //read data.txt file
if ( fdata == NULL )
{
printf("could not read file %s\n", argv[1] );
exit( 0 );
}
fgets( data, 100, fdata );
while ( ! feof( fdata ) )
{
printf("data: %s", data);
//this is where i get stuck, idk how to utilize this loop to copy the variable and variable names from the data.txt file i was given...thanks for the help
/* count how many token characters there are in data[] string */
num_token = Count_Token( data, '=' );
if ( num_token > MAX )
{
printf(" num token is %d, MAX is %d, stopping program.\n", num_token, MAX );
fclose( fdata );
exit( 0 );
}
for ( i = 0; i < num_token; i++ )
{
/* make sure i index does not exceend declaration size of key and value */
Get_KeyValue_at_Position( data, token, i, key[i], value[i] );
}
fgets( data, 100, fdata );
}
fclose(fdata);
return 0;
}