统计单词个数及词频（C++实现）

#include<iostream>
#include<fstream>
#include<string>

using namespace std;

struct Word       //定义结构体
{
string word;
size_t length;
Word* next;
int repnum;//repeat number 重复次数
bool ifdel;//if delete 是否被删除
Word(string _word, size_t _lendth = 0, Word* _next = NULL, int _repnum = 1, bool _ifdel = false) :
word(_word), length(_lendth), next(_next), repnum(_repnum), ifdel(_ifdel){}
};

Word *head = NULL, *tail = NULL;
int size = 0;  //链表长度，即单词总个数
int delsum = 0;//delete sum 被删除的总个数

void Push(const string& str, const size_t& len)   //形成链表
{
if (NULL == head)
{
head = tail = new Word(str, len, NULL, 1, false);
}
else
{
tail->next = new Word(str, len, NULL, 1, false);
tail = tail->next;
}
size++;
}

void Destory()   //delete new
{
Word* ptr = head;
while (ptr)
{
Word* pt = ptr;
ptr = ptr->next;
delete pt;
}
head = tail = NULL;
size = 0;
}

void Readin(string& mystr)   //read in  读入
{
string temps;
for (size_t i = 0; i < mystr.length(); i++)
{
if (mystr[i] >= 'a'&&mystr[i] <= 'z' || mystr[i] >= 'A'&&mystr[i] <= 'Z')
{
temps += mystr[i];
}
else
{
if (!temps.empty())//不空的时候返回0
{

Push(temps, temps.length());
temps.erase(temps.begin(), temps.end());
}
}
}
}
void DeSame()      //delete the same 删除相同的单词（不是真删，只是做标记）
{
Word* p = head;
while (p&&p->next)
{
while (p->ifdel&&p->next)
{
p = p->next;
}
Word* pt = p->next;
while (pt)
{
if (!pt->ifdel&&pt->word == p->word)
{
p->repnum++;
pt->ifdel = true;
delsum++;
}
pt = pt->next;
}
p = p->next;
}
}

void Inputp(Word* warr[])   //input point 将未被“删除”的结点的指针传入数组
{
int i = 0;
Word* pt = head;
while (pt)
{
if (!pt->ifdel)
{
warr[i] = pt;
i++;
}
pt = pt->next;
}
}

void Sort(Word** warr, int start, int end)   //将指针按其指向的结点的repnum从大到小排序，快排实现
{
int i = 0, j = 0;
Word* key = NULL;
key = warr[start];
i = start;
j = end;
while (i<j)
{
while (warr[j]->repnum <= key->repnum&&i<j)j--;
warr[i] = warr[j];
while (warr[i]->repnum >= key->repnum&&i<j)i++;
warr[j] = warr[i];
}
warr[i] = key;
if (i - 1>start)Sort(warr, start, i - 1);
if (end > i + 1)Sort(warr, i + 1, end);
}

void Show(Word** warr, int len)
{
for (int i = 0; i < len; i++)
{
cout << warr[i]->word << "  " << warr[i]->repnum << endl;
}
}

int main()
{
ifstream readfile("zpc.txt", ios::in);
if (!readfile){ cout << "程序出现异常，自动退出！" << endl; return 0; }
string str, str1;
while (!readfile.eof())
{
getline(readfile, str1);
str += str1;
str += ' ';
}
readfile.close();
Readin(str);
DeSame();
cout << "单词总个数（不考虑重复）：" << size << endl;
cout << "除去重复后的单词个数（即重复的单词按1个计）：" << size - delsum << endl;
Word** wdarr = new Word*[size - delsum];
Inputp(wdarr);
Sort(wdarr, 0, size - delsum - 1);
Show(wdarr, size - delsum);
delete[]wdarr;
Destory();
return 0;
}