1:编写函数，当字符串出现在另一个字符串的尾部，该函数返回1 否则0

2:根据单词的出现频率按降序打印输入的各个不同单词，并在每个单词的前面标上它的出现次数。

3:大小写字母转换

4:比较两个文件并打印它们第一个不相同的行

5:打印一个文件集合，每个文件从新的一页开始打印，并且打印每个文件相应的标题和页数-1: write the function, if the string appears in another string in the tail, the function returns 1 or 0 2: According to the word printed in descending order the frequency of the different input words, and in front of each word marked on it number of occurrences. 3: upper and lowercase letters converted 4: compare two files and print them different from the first line 5: Print a document collection, each document of a new start printing, and print each file corresponding title and page