#define loglen sizeof(log)
#define paslen sizeof(pas)
#define fillen sizeof(fil)
#define textlen sizeof(texter)
#define goend fseek(fp,0L,2)
typedef struct
{
char username[15];
long link;
long nextuser;
}log;
typedef struct
{
char password[15];
long link1;
long nextpass;
}pas;
typedef struct
{char filename[15];
int pcode;
int length;
long addr;
long nextfile;
}fil;
typedef struct
{char text[20];
long nexttext;
}texter;
strcopy(char *s1,char *s2,int n)
{int i;
 for(i=0;i<n;i++) *(s1+i)=*(s2+i);
 *(s1+i)='\0';}