UVA 10815（字符串）

题目：Andy, 8, has a dream - he wants to produce his very
own dictionary. This is not an easy task for him, as
the number of words that he knows is, well, not quite
enough. Instead of thinking up all the words himself,
he has a briliant idea. From his bookshelf he would
pick one of his favourite story books, from which he
would copy out all the distinct words. By arranging
the words in alphabetical order, he is done! Of course,
it is a really time-consuming job, and this is where a
computer program is helpful.
You are asked to write a program that lists all
the different words in the input text. In this problem,
a word is defined as a consecutive sequence of
alphabets, in upper and/or lower case. Words with
only one letter are also to be considered. Furthermore, your program must be CaSe InSeNsItIvE. For
example, words like “Apple”, “apple” or “APPLE” must be considered the same.
Input
The input file is a text with no more than 5000 lines. An input line has at most 200 characters. Input
is terminated by EOF.
Output
Your output should give a list of different words that appears in the input text, one in a line. The words
should all be in lower case, sorted in alphabetical order. You can be sure that he number of distinct
words in the text does not exceed 5000.
Sample Input
Adventures in Disneyland

Two blondes were going to Disneyland when they came to a fork in the

road. The sign read: "Disneyland Left."
So they went home.
Sample Output
a
adventures
blondes
came
disneyland
fork
going
home

in

left
read
road
sign
so
the
they
to
two
went
were
when

题意：将所有单词以小写形式按照从小到大（a比b小）存入。

思路：冯盛源的思路就是用isalpha来判断作为一个单词的结束，循环结束后数组里存有所有的单词，然后用qsort函数排大小，最后判断前一个单词是否比后一个大来控制重复的单词。（主要学到了他的思路以及两个函数isalpha和qsort的用法）。

#include<stdio.h>#include<stdlib.h>#include<ctype.h>#include<string.h>int comp(const void*a,const void *b){return strcmp((char*)a,(char*)b);}char s[27050][250];int main(void){char ch;int k=0,j=0;/*while((ch=getchar())!=EOF) {if(ch==' '||ch=='\n'){s[j][k]='\0';j++;k=0;}s[j][k]=tolower(ch);k++;}*/while((ch=getchar())!=EOF) {if(isalpha(ch)) {s[j][k++]=tolower(ch);}else if(k) {s[j][k]='\0';j++;k=0;}}qsort(s,j,sizeof(s[0]),comp);for(k=0;k<j;k++)if(strcmp(s[k],s[k+1]))printf("%s\n",s[k]);return 0;}