接着打断点，进行常规调试，查看程序的运行的情况：
(gdb) b 14
Breakpoint 1 at 0x400524: file add.c, line 14.
(gdb) r
Starting program: /home/heamon7/Project/test/add
Breakpoint 1, main (argc=1, argv=0x7fffffffe658) at add.c:14
14 result = add(a,b);
(gdb) p a
$1 = 1
(gdb) p b
$2 = 2
(gdb) p result
$3 = 0
(gdb) s
add (a=1, b=2) at add.c:4
4 result = a + b;
(gdb) s
6 return result;
(gdb) s
7 }
(gdb) p result
$4 = 3
(gdb) c
Continuing.
[Inferior 1 (process 23833) exited normally]
(gdb)