(gdb) run
Starting program: /student/mac/JD/Desktop/data
Reading symbols for shared libraries ++......................... done
Enter the first list in ascending order.
How many nodes:4
Enter 4 Eelements:4 5 6 7
Enter the Second list in ascending order.
How many nodes:4
Enter 4 Eelements:4 5 6 7
The first list is:4->'5->'6->'7->'The second list is
Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_INVALID_ADDRESS at address: 0x0000000000000008
0x00000001000009ff in list::merge (this=0x7fff5fbff9f0, l1={start = 0x100100a30}, l2={start = 0x100100a70}) at Node.cc:86
86 pre_node->next=nxt_node;