给出一段英文，统计单词出现的次数

#include <iostream>#include <map>#include <fstream>#include <string>using namespace std;int main(){string filename;cin>>filename;ifstream input(filename,ios::in);//打开文件if(input.fail()){cout<<"打开文件失败，请检查输入是否正确！\n";system("puase");return 0;}map<string, int> wordCount;  //关联容器string word;while (input>> word)  //统计单词出现次数++wordCount[word];input.close();  //关闭文件string result;cout<<"请输入保存统计结果的文件名！\n";cin>>result;ofstream output(result,ios::out);  //创建文件if(output.fail()){cout<<"创建文件失败！\n";system("puase");return 0;}//向指定文件输出统计结果for (map<string, int>::iterator it = wordCount.begin(); it != wordCount.end(); ++it)output<<(*it).first<<' '<<(*it).second<<"次"<<endl;output.close();//关闭文件return 0;}