gcc -g eg.c -o eg

#include 
int wib(int no1, int no2)
{
  int result, diff;
  diff = no1 - no2;
  result = no1 / diff;
  return result;
}
int main(int argc, char *argv[])
{
  int value, div, result, i, total;
  value = 10;
  div = 6;
  total = 0;
  for(i = 0; i < 10; i++)
  {
    result = wib(value, div);
    total += result;
    div++;
    value--;
  }
  printf("%d wibed by %d equals %d\n", value, div, total);
  return 0;
}

Program received signal SIGFPE, Arithmetic exception.
0x80483ea in wib (no1=8, no2=8) at eg1.c:7
7         result = no1 / diff;
(gdb)

(gdb) print no1
$5 = 8
(gdb) print diff
$2 = 0

(gdb) continue
Continuing.
Program terminated with signal SIGFPE, Arithmetic exception.
The program no longer exists.

(gdb) break 21
Breakpoint 1 at 0x8048428: file eg1.c, line 21.

Breakpoint 1, main (argc=1, argv=0xbffff954) at eg1.c:21
21          result = wib(value, div);

(gdb) next
22          total += result;

(gdb)
23          div++;
(gdb)
24          value--;

(gdb) break 21 if value==div
Breakpoint 1 at 0x8048428: file eg1.c, line 21.

(gdb) condition 1 value==div

(gdb) info break
Num Type           Disp Enb Address    What
1   breakpoint     keep y   0x08048428 in main at eg1.c:21
        stop only if value == div
        breakpoint already hit 1 time

(gdb) break main
Breakpoint 1 at 0x8048402: file eg1.c, line 15.
(gdb) run
...
Breakpoint 1, main (argc=1, argv=0xbffff954) at eg1.c:15
15        value = 10;

(gdb) watch div==value
Hardware watchpoint 2: div == value

(gdb) continue
Continuing.
Hardware watchpoint 2: div == value
Old value = 0
New value = 1
main (argc=1, argv=0xbffff954) at eg1.c:19
19        for(i = 0; i < 10; i++)

$ ./eg1
Floating point exception (core dumped)

...
Core was generated by `./eg1'.
Program terminated with signal 8, Floating point exception.
...
#0  0x80483ea in wib (no1=8, no2=8) at eg1.c:7
7         result = no1 / diff;

(gdb) bt
#0  0x80483ea in wib (no1=8, no2=8) at eg1.c:7
#1  0x8048435 in main (argc=1, argv=0xbffff9c4) at eg1.c:21

(gdb) frame 1
#1  0x8048435 in main (argc=1, argv=0xbffff9c4) at eg1.c:21
21          result = wib(value, div);
(gdb) info locals
value = 8
div = 8
result = 4
i = 2
total = 6

#include 
int main(int argc, char *argv[])
{
  int i;
  for(i = 0; i < 60; i++)
  {
    sleep(1);
  }
  return 0;
}

./eg2 &
[3] 1283

...
/home/seager/gdb/1283: No such file or directory.
Attaching to program: /home/seager/gdb/eg2, Pid 1283
...
0x400a87f1 in __libc_nanosleep () from /lib/libc.so.6
(gdb)

(gdb) backtrace
#0  0x400a87f1 in __libc_nanosleep () from /lib/libc.so.6
#1  0x400a877d in __sleep (seconds=1) at ../sysdeps/unix/sysv/linux/sleep.c:78
#2  0x80483ef in main (argc=1, argv=0xbffff9c4) at eg2.c:7
(gdb) frame 2
#2  0x80483ef in main (argc=1, argv=0xbffff9c4) at eg2.c:7
7           sleep(1);
(gdb) print i
$1 = 50

Breakpoint 1, wib (no1=8, no2=8) at eg1.c:7
7         result = no1 / diff;
(gdb) print diff
$1 = 0
(gdb) set diff=1
(gdb) continue
Continuing.
0 wibed by 16 equals 10
Program exited normally.