急！C语言操作文件的问题，帮忙啊
要求:
1) 用C语言程序计算Answer_timestamp 字段不为空的记录条数，并且计算此时对应的conversation duration字段里面所有时间的和（十分之一秒格式的），然后用 Unix 脚本运行（⊙⊙b汗，真没做过这些）
2）计算出所有符合条件的conversation duration字段的和，除以600，得到分钟数
3) 输入文件名和输出文件名最好以变量的形式表示，便于以后修改，重用

4) 输出格式如下:
Convdur = 9999999999 mins
Callans = 9999999999

注意 :
a) 十分之一秒的时间通过除以600，转换为分钟
b) 被操作文件中，含有多条记录，一行就是一条记录，记录中不同的字段用逗号（,）隔开的（文件内容附后面）
c）每条记录中，第6个字段是Answer_timestamp字段的值（如：2007-11-28 00:00:00.0），第12个字段是conversation_duration的值(如：17711，是十分之一秒的格式)
d）当Answer_timestamp字段为空（space）时，conversation_duration字段的值为0
e）这个程序只涉及2个字段，由于下面的文件内容很多，很乱，只找对应字段就可以了

下面是操作的字段说明和记录文件片段：

字段说明：
NoDescriptionAttributes

1DatadateChar (10)
YYYY-MM-DD
2Call_record_idChar (44)
3ExchidChar (3)
4In_Seizure_timestamp
Char (21)
YYYY-MM-DD HH:MI:SS.T
5Out_Seizure_timestampChar (21)
YYYY-MM-DD HH:MI:SS.T
6Answer_timestampChar (21)
YYYY-MM-DD HH:MI:SS.T
7Disconnect_timestampChar (21)
YYYY-MM-DD HH:MI:SS.T
8B_number_prefixChar (10)
9B_number_ctrycodeChar (4)
10B_numberChar (18)
11Distant_countryChar (3)
12Conversation DurationNum (10)

13Short_long_dur_indChar (1)
14Ic_destination_areaChar (2)
15Og_destination_area Char (2)
16Ic_National_area Char (8)
17Og_National_area Char (8)
18Ic_trunkNum (5)
19Ic_carrierChar (20)
20Og_trunkNum (5)
21Og_carrierChar (20)
22Call_completion_codeChar (3)
23Traffic_directionChar (1)
24Routing_methodChar (1)
25Traffic_classChar (10)
26Distant_carrierChar (20)
27Origin_carrierChar (20)
28Origin_countryChar (3)
29A-Party-NbrChar (19)
30CPCChar (3)
31Office Point Code ReceivedChar (6)
32Office Point Code SentChar (6)
33Digit Outpulsed NbrChar (24)
34Called NumberChar (24)
35Additional Calling NumberChar (20)
36Translated NumberChar (24)
37Billed NumberChar (24)
38Outgoing Circuit Identification CodeChar (5)
39Incoming Circuit Identification CodeChar (5)
40Cause of Call EndChar (1)
41Org_Ic_trunkNum (5)
42Org_Og_trunkNum (5)
Total Length486


2010-03-08,O584056774#P582144535,OGT,2010-03-08 14:14:30.2,2010-03-08 14:14:30.9,2010-03-08 14:14:32.2,2010-03-08 14:44:03.9, ,65,63073744,SNG,17711,N,N,N, ,STF,1284,HKTI,531,SINLOC,0,I,D,IB_ITFS_F, ,HKTI,HKG,A0,10,9057, , ,1309852919, ,6563073744,000002710,138,2,1,1284,531,
2010-03-08,O580751526#P579794577,OGT,2010-03-08 11:10:28.8,2010-03-08 11:10:29.2,2010-03-08 11:10:30.5,2010-03-08 11:55:14.1,154002,60,321719203,MLA,26836,N,M4,M4, , ,3758,DWS-EQUANT-P,1794,TM-RCDT,0,T,D,DWSP, , , ,68835060,229,1549, , ,15400260321719203, , , ,661,374,1,855,1794,
2010-03-08,V813660587F#,SGT,2010-03-25 23:27:21.1,2010-03-25 23:27:21.2, ,2010-03-25 23:27:30.2,01010070,65,97316565,SNG,0,U,O,O, ,STM,3142,SSS-V2-PCCW-V,9198,SINLOC,172,I,D,IDD, , , ,8613150660776, , , ,97316565,010100706597316565, , , , , ,2,8024,520,
2010-03-08,O813669528F#,OGT,2010-03-25 23:29:03.5,2010-03-25 23:29:07.8, ,2010-03-25 23:29:10.8, ,229,1419397,BEN,0,U,N,N, , ,1737,DST,8015,SSS-V2-LEXICO,75,T,I,IDD, , , ,6738837827,10,10692,10649,2291419397,2291419397, , , ,76,37,3,1737,8015,
2010-03-08,V813711841F#,SGT,2010-03-25 23:37:00.2, , ,2010-03-25 23:37:15.5, ,65,90082734,SNG,0,U,O,O, ,SHM,5020,SSH-HUTCHISON-V,0, ,102,I, ,IDD, , , ,0,10, , ,90082734,90082734, , , , , ,2,5020,0,
2010-03-08,V813663861F#,SGT,2010-03-25 23:37:02.7, , ,2010-03-25 23:37:03.5, ,65,94992153,SNG,0,U,O,O, ,SHM,5007,SSH-STHK-V,0, ,41,I, ,IDD, , , ,0,10, , ,94992153,94992153, , , , , ,2,5007,0,