Puzzling question

冰之吻

#include "stdio.h"
#include "string.h"
#include "stdlib.h"
#include "time.h"

#define MAX_PKT 1024

#define MAX_SEQ 7

typedef enum {FALSE, TRUE} boolean;

typedef unsigned int seq_nr;

typedef enum {dat, ack, nak} frame_kind;

typedef enum event_type {timeout, frame_arrival};

typedef struct
{frame_kind kind;
seq_nr seq;
seq_nr ack;
char info [1024];
} frame;

void from_network_layer (frame * fra)
{
printf ("Input information:");
memset (fra-> info, 0, strlen (fra-> info));
for (int i = 0;; i ++)
{
fra-> info [i] = getchar ();
if ('\n' == fra-> info [i])
{
fra-> info [++ i] = '\0';
break;
}
}
}

void to_physical_layer (frame * fra)
{
FILE * fp1;
char buf [1024];
char temp;
memset (buf, 0, strlen (buf));
switch (fra-> kind)
{
case dat:
strcpy (buf, "dat");
break;
case ack:
strcpy (buf, "ack");
break;
case nak:
strcpy (buf, "nak");
break;
}
itoa (fra-> ack,&temp, 10);
strcat (buf,&temp);

itoa (fra-> seq,&temp, 10);
strcat (buf,&temp);

strcat (buf, fra-> info);
// strcat (buf, '/ 0');
if (0 == (fp1 = fopen ("d:\\a.txt", "r")))
{
printf ("File creation failed");
fclose (fp1);
}
else
{
fwrite (buf, 1, 1024, fp1);
fclose (fp1);
}
printf ("success");
}

event_type wait_for_event ()
{
      return frame_arrival;
}
void main ()
{
seq_nr ack = 0;
frame send, rev;
event_type event;
from_network_layer (&send);
send.kind = dat;
send.ack = 0;
send.seq = 0;
to_physical_layer (&send);
         event = wait_for_event ();
}
As soon as you debug to WAIT_FOR_EVENT () RETURN, UNHANDLED EXCEPTION is displayed.If TO_PHYSICAL_LAY () is shielded, you can return normally. The master will give pointers, thank you first!

orangedj

memset (buf, 0, sizeof (buf));

orangedj

char temp [16];
.....
itoa (fra-> ack, temp, 10);

orangedj

printf ("File creation failed");
// fclose (fp1); This close is removed

And all of the above itoas

冰之吻

Thank you, how do you discover these problems?

orangedj

printf the contents of buf

orangedj

And fopen "wb"

stoneboy4000

memset has not seen strlen, and still uses strlen for initialization, otherwise use strcpy ()
fp1 file creation failed, fclose (fp1) will definitely not be used;

As for itoa (fra-> ack,&temp, 10); because it is a statically allocated char [16],&temp and temp are the same and point to the first address of the allocated space.
If it is malloc dynamic allocation,&temp points to the variable that stores the address value, you must use temp

zxs11180809

char temp [16];
.....
itoa (fra-> ack, temp, 10);