|
Subject:
|
declaring structs
|
|
Posted By:
|
scoobie
|
Post Date:
|
11/12/2005 5:55:51 PM
|
Hi,
i'm new to c programming. i have declared a typedef struct that contains two arrays in it. the problem is when i try to reference something that is in the struct i get an error. here is the code
#include <stdio.h>
#include <stdlib.h>
typedef struct
{
unsigned short key1[2];
unsigned short plain[2];
}code;
unsigned short *res_k1;
unsigned short *res;
main(int argc, char *argv[])
{
unsigned short k1[2],k2[2];
unsigned short p[2],c[2];
res_k1 = (unsigned short *) malloc(sizeof (code));
k1[0]=0x0000;
k1[1]=0x0000;
short i;
p[0]=0x0001;
p[1]=0x0002;
for (i=0; k1[0] < 0x00FF; i++)
{
for (i=0; k1[1] < 0xFFFF; i++)
{
encode(p, k1);
printf(" Result = ");
printf("(%4x,%4x) ",p[0],p[1]);
}
encode(p, k1);
printf(" Result = ");
printf("(%4x,%4x) ",p[0],p[1]);
}
} //end main
also i declare an array unsigned short[17000000]; does anybody know i pass in the results of p to that array;
thanks in advanced for all you help,
sc
|
|
Reply By:
|
Paramesh
|
Reply Date:
|
11/13/2005 5:08:05 AM
|
Please be more specific.
Post the error message you get.
"Don't walk behind me; I may not lead.
Don't walk in front of me; I may not follow.
Just walk beside me and be my friend."
|
|
Reply By:
|
scoobie
|
Reply Date:
|
11/19/2005 10:24:47 AM
|
hi,
i managed to get my struct to work.the problem i am having now is i am trying to use calloc memory allocation but i keep getting a segmentation fault and i don't know how to fix it. i don't think i am declaring the calloc properly and storing the result of encode properly.
here is my code that i am using.
#include <stdio.h>
#include <stdlib.h>
typedef struct code1
{
unsigned short key[2];
unsigned short text[2];
}code;
void encode(short* v, short* k)
{ ... }
void decode(short* v,short* k)
{ ... }
main(int argc, char *argv[])
{
unsigned short key1[2],key2[2];
unsigned short p[2],c[2];
struct code1 *test, *entry;
entry = (unsigned short *) calloc(2, sizeof (code));
key1[0]=0x0000;
key1[1]=0x0000;
short i;
p[0]=0x0001;
p[1]=0x0002;
for (i=0; key1[0] < 0x0002; i++)
{
for (i=0; key1[1] < 0x000A; i++)
{
encode(p, key1);
test[i].key[0] = key1[0];
test[i].key[1] = key1[1];
test[i].text[0] = p[0];
test[i].text[1] = p[1];
}
}
} //end main
can anybody help?
thanks,
sc
|
|
Reply By:
|
C@uark
|
Reply Date:
|
4/6/2006 12:44:25 AM
|
change:
entry = (unsigned short *) calloc(2, sizeof (code));
you have declared "entry" as a pntr to a code1 structure so when you call calloc type cast it to the appropriate type.
entry = ( struct code1* ) calloc(2, sizeof (code)); // >>first arg is the number of elements in an array you
//wish to allocate.<<
// >>second arg is the size of each element, in
// in this case the size of a code1/code structure.<<
calloc always returns a void pntr or NULL if insufficient memory, you must type cast it to the type of the receiving variable in this case a struct code1*.
Now since you have dynamically allocated the memory for "entry" you would also dereference the structure member variables by using the indirect access operator -> i.e. entry[i]->key[0] = key1[0]; // i being the subscript into the array of structs that you have allocated
|
