用STL解决单词统计程序

以前看到有人出了一道单词统计题，意思大概是， 有一个words.txt文件的内容如下：

some

are

born

great

some

achieve

greatness

and

some

have

greatness

thrust

upon

them

用程序读取该文件，统计相同的单词数，并按字符顺序写入另一个文件，如result.txt

achieve 1

and 1

are 1

born 1

great 1

greatness 2

have 1

some 3

them 1

thrust 1

upon 1

现用两种STL方法(即vector和map)解如下：

/////////////////////////////////vector//////////////////////////

Code:

#include <fstream>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;

struct Count
{
string name;
double val;
Count(string n="",double v=0):name(n),val(v){}
};

bool sort_name(const Count & m1, const Count & m2)
{
return strcmp(m1.name.c_str(),m2.name.c_str())<=0 ? true:false;
}

vector<Count> counts;
double& value(const string& s)
{
for (int i=0;i<counts.size();i++)
{
if (s==counts[i].name)
return counts[i].val;
}
counts.push_back(Count(s));

return counts[counts.size()-1].val;
}

int main()
{

ifstream ifs("words.txt");
string buf;

while(ifs)
{
if(getline(ifs,buf))
value(buf)++;
}
ifs.close();
sort(counts.begin(), counts.end(),sort_name);
ofstream ofs("result.txt");
for(vector<Count>::const_iterator p=counts.begin();p!=counts.end();++p)
{
cout<<p->name<<'/t'<<p->val<<'/n';
ofs<<p->name<<'/t'<<p->val<<'/n';
}
ofs.close();
return 0;
}

//////////////////////////////////////////////map/////////////////////////////////////////

Code:

#include <fstream>
#include <iostream>
#include <string>
#include <map>
#include <algorithm>
using namespace std;

typedef map<string,int>::const_iterator CI;

void Insert(map<string,int>& m)
{
string word;
int val=1;
ifstream ifs("words.txt");
while (ifs)
{
if(getline(ifs,word))
m[word]+=val;
}
ifs.close();
}

int main()
{
map<string,int> tbl;
Insert(tbl);
ofstream ofs("result.txt");
for (CI p=tbl.begin();p!=tbl.end();++p)
{
cout<<p->first<<'/t'<<p->second<<'/n';
ofs<<p->first<<'/t'<<p->second<<'/n';
}
ofs.close();
return 0;
}