《CPlusPlusPrimer》第十二章二节编程源码——vocab功能的源码

用于练习泛型算法。

程序源码：

// 练习C++Primer Chapter12.2节中的泛型算法#include <iostream>#include <fstream>#include <algorithm>#include <vector>#include <string>using namespace std;typedef vector<string> textwords;typedef vector<string>::iterator VEC_STR_IT;class PrintElem{int line_len;int cnt;public:PrintElem(int len = 8): line_len(len), cnt(0) {}void operator()(const string & elem){cnt++;cout << elem << " ";if( cnt % line_len == 0){cout << '\n';}}};class LessThan{public:bool operator()(const string &str1, const string &str2){// OK，必须用size，而非length.return (str1.size() < str2.size());}};class GreatThan{int _len;public:GreatThan(int len = 6) : _len(len) {}bool operator() ( const string & s){return (s.size() > _len);}};void proccess_vocab(const vector<textwords> &vecs){vector<string> texts;vector<textwords>::const_iterator iter = vecs.begin();for( ; iter != vecs.end(); iter++ ){copy( (*iter).begin(), (*iter).end(), back_inserter( texts ));}sort( texts.begin(), texts.end() );for_each( texts.begin(), texts.end(), PrintElem());cout << "\n\n";// 消除相同词VEC_STR_IT it;it = unique( texts.begin(), texts.end());texts.erase(it, texts.end());for_each( texts.begin(), texts.end(), PrintElem());cout << "\n\n";// 根据自符串长度排序stable_sort( texts.begin(), texts.end(), LessThan());for_each( texts.begin(), texts.end(), PrintElem());cout << "\n\n";// 计算长度大于6的个数int cnt  = count_if( texts.begin(), texts.end(), GreatThan());cout << "the count which's size is great than 6 is: " << cnt << endl;static string rw[] = {"and", "if", "or", "but", "the"};vector<string> remove_words ( rw, rw + 5);VEC_STR_IT it2 = remove_words.begin();for( ; it2 != remove_words.end(); it2++ ){int cnt = count ( texts.begin(), texts.end(), *it2);cout << cnt << " instances removed: " << (*it2) << endl;texts.erase(remove(texts.begin(), texts.end(), (*it2)),texts.end());}cout << "\n\n";for_each( texts.begin(), texts.end(), PrintElem());}int main( char* args[], int argc){vector<textwords> sample;vector<string> vec1, vec2;const string inf1 = "chapter12_vocab_file1.txt", inf2 = "chapter12_vocab_file1.txt";using std::ifstream;ifstream infile1(inf1.c_str());ifstream infile2(inf2.c_str());istream_iterator<string> input_set1(infile1), eos;istream_iterator<string> input_set2(infile2);copy( input_set1, eos, back_inserter(vec1));copy(input_set2, eos, back_inserter(vec2));sample.push_back( vec1 );sample.push_back( vec2 );proccess_vocab(sample);return 0;}

运行部分截图：