设计string类



要求：

1、为该类定义构造函数,析构函数和赋值操作。构造函数至少应有三个：无参构造函数、C风格字符串构造函数和复制构造函数



2、为string类提供必要的成员函数，可以参考C++类库的string类提供了那些成员函数，至少应包括下标访问，子串查找、获得C风格字符串、获得字符串长度、字符串比较这几个函数



3、利用该string类完成测试程序:统计一个文本文件中所有包含给定子串的单词，并按字典序无重复的打印输出这些单词-Design string class



Requirements:

1, defined for the class constructor, destructor and assignment operator. The constructor should be at least three: the no-argument constructor, C-style string

Constructor and copy constructor



Provide the necessary member function for the string class, you can refer to the C library string class provided that the member function should include at least

Subscr ipt to access, substring searches, access to C-style string to get the length of the string, the string comparison of these functions are



3, using the string class to complete the test program: Statistics in a text file containing words to the substring, according to the lexicographic repeat

Printout of these