[求助]一道三级C语言上机题。

函数ReadDat( )实现从文件IN.DAT中读取一篇英文文章存入到字符串数组xx中; 请编制函数StrOL( ), 其函数的功能是: 以行为单位对行中以空格或标点符号为分隔的所有单词进行倒排，同时去
除标点符号，之后把已处理的字符串(应不含标点符号)仍按行重新存入字符串数组xx中。最后main()函数调用函数WriteDat()把结果xx输出到文件OUT6.DAT中。
例如: 原文: You He Me
I am a student.
结果: Me He You
student a am I
原始数据文件存放的格式是: 每行的宽度均小于80个字符, 含标点符号和空格。
PROG1.C
# include"stdio.h"
# include"string.h"
# include"conio.h"
# include"ctype.h"
char xx[50][80];
int maxline=0;

int ReadDat(void);
void WriteDat(void);

void StrOR(void)
{
}

void main()
{clrscr();
if(ReadDat())
{printf("Can't open the file!\n");
return;}
StrOR();
WriteDat();
system("pause");
}

int ReadDat(void)
{FILE *fp;int i=0;char *p;
if((fp=fopen("in.dat","r"))==NULL) return 1;
while(fgets(xx,80,fp)!=NULL)
{p=strchr(xx,'\n');
if(p) *p=0;
i++;
}
maxline=i;
fclose(fp);
return 0;
}

void WriteDat(void)
{FILE *fp;
int i;
fp=fopen("out.dat","w");
for(i=0;i<maxline;i++)
{printf("%s\n",xx);
fprintf(fp,"%s\n",xx);
}
fclose(fp);
}


IN.DAT
You He Me
I am a student
You can create an index on any field, on several fields to be used
together, or on parts thereof, that you want to use as a key. The
keys in indexes allow you quick access to specific records and define
orders for sequential processing of a ISAM file. After you no longer
need an index, you can delete it. Addition and indexes have no effect
on the data records or on other indexes.
You may want a field in field in each record to uniquely identify that
record from all other records in the file. For example, the Employee
Number field is unique if you do not assign the same number to two
different employees, and you never reassign these numbers to other
employees. If you wish to find or modify the record belonging to a
specific employee, this unique field saves the thouble of determining
whether you have the correct record.
If you do not have a unique field, you must find the first record
the matches your key and determine whether the record is the one you
want. If it is not the correct one, you must search again to find others.
If you know that you have a unique field within your records, you
can include this fact in the key description, and ISAM will allow only
unique keys. For example, if you specify that the employee numbers are
unique, ISAM only lets you add records to the file for, or change
numbers to, employee numbers that do not alreadly exist int file.

OUT.DAT
Me He You
student a am I
used be to fields several on field any on index an create can You
The key a as use to want you that thereof parts on or together
define and records specific to access quick you allow indexes in keys
longer no you After file ISAM a of processing sequential for orders
effect no have indexes and Addition it delete can you index an need
indexes other on or records data the on
that identify uniquely to record each in field in field a want may You
Employee the example For file the in records other all from record
two to number same the assign not do you if unique is field Number
other to numbers these reassign never you and employees different
a to belonging record the modify or find to wish you If employees
determining of thouble the saves field unique this employee specific
record correct the have you whether
record first the find must you field unique a have not do you If
you one the is record the whether determine and key your matches the
others find to again search must you one correct the not is it If want
you records your within field unique a have you that know you If
only allow will ISAM and description key the in fact this include can
are numbers employee the that specify you if example For keys unique
change or for file the to records add you lets only ISAM unique
file int exist alreadly not do that numbers employee to numbers
答案程序是：
void StrOL(void)
{ int i,j,k,m,n,ll;
char yy[80];
for(i=0; i < maxline; i++)
{ ll=strlen(xx); k=n=0;
for(j=ll-1; j>=0; j--)
{ if(isalpha(xx[j])) k++;
else
{ for(m=1; m<=k; m++)
yy[n++]=xx[j+m]; k=0; }
if(xx[j]==' ') yy[n++]=' ';
}
for(m=1; m<=k; m++) yy[n++]=xx[j+m];
yy[n]=0; strcpy(xx,yy);
}
}
不知道算法的思想。哪位好人指点迷津。
多谢。

答案都有了,还用那么费劲在这问吗,有时间上机调试一下也比这强啊.程序是练的不是看的.