using structure result in one file into another file? - c

Question

I have two files: p1.c and p2.c.
I need to use the value stored in the structure in p1.c into p2.c. Please help me figure out how to achieve this. Should I use extern?
p1.c
typedef struct What_if
{
char price[2];
} what_if ;
int main()
{
what_if what_if_var[100];
file * infile;
infile=fopen("filepath");
format_input_records();
}
int format_input_records()
{
if ( infile != NULL )
{
char mem_buf [500];
while ( fgets ( mem_buf, sizeof mem_buf, infile ) != NULL )
{
item = strtok(mem_buf,delims);
strcpy(what_if_var[line_count].price,item) ;
printf("\ntrans_Indicator ==== : : %s",what_if_var[0].price);
}
}
}
p2.c
"what_if.h" // here i include the structure
int main()
{
process_input_records(what_if_var);
}
int process_input_records(what_if *what_if_var)
{
printf("\nfund_price process_input_records ==== : : %s",what_if_var[0]->price);
return 0;
}

Answer 1

Try this:
whatif.h:
#ifndef H_WHATIF_INCLUDED
#define H_WHATIF_INCLUDED
struct whatif {
char price[2];
};
int wi_process(struct whatif *);
#endif
p1.c
#include "whatif.h"
int main(void) {
struct whatif whatif[100];
whatif[0].price[0] = 0;
whatif[0].price[1] = 1;
whatif[1].price[0] = 42;
whatif[1].price[1] = 74;
whatif[99].price[0] = 99;
whatif[99].price[1] = 100;
wi_process(whatif);
return 0;
}
p2.c
#include <stdio.h>
#include "whatif.h"
int wi_process(struct whatif *arr) {
printf("%d => %d\n", arr[0].price[0], arr[0].price[1]);
printf("%d => %d\n", arr[1].price[0], arr[1].price[1]);
printf("%d => %d\n", arr[99].price[0], arr[99].price[1]);
return 3;
}
Then compile and link all of them together, for example with gcc
gcc -ansi -pedantic -Wall p1.c p2.c