Created
July 31, 2014 06:05
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| #include <chrono> | |
| #include <iostream> | |
| #include <string> | |
| #include <sstream> | |
| using namespace std; | |
| class stopwatch | |
| { | |
| std::chrono::high_resolution_clock::time_point start; | |
| public: | |
| stopwatch() | |
| : start(std::chrono::high_resolution_clock::now()) | |
| { | |
| } | |
| ~stopwatch() | |
| { | |
| auto duration = std::chrono::high_resolution_clock::now() - start; | |
| cerr << std::chrono::duration_cast<std::chrono::milliseconds>(duration).count() << " ms" << endl; | |
| } | |
| }; | |
| class ss | |
| { | |
| const char *p_; | |
| public: | |
| ss(const char *p) | |
| : p_(p) | |
| { | |
| } | |
| int get() | |
| { | |
| return *p_++; | |
| } | |
| void unget() | |
| { | |
| p_--; | |
| } | |
| }; | |
| template<typename Pred, typename Stream> | |
| static string read_while(Pred pred, Stream &is) | |
| { | |
| char ch; | |
| string s; | |
| while ((ch = is.get()) && pred(ch)) | |
| s += ch; | |
| is.unget(); | |
| return s; | |
| } | |
| int main() | |
| { | |
| istringstream is("hello world!"); | |
| for (int k = 10; --k > 0; ) | |
| { | |
| stopwatch sw; | |
| for (int i = 5000000; --i > 0; ) | |
| { | |
| //is.seekg(is.beg); | |
| ss is2("hello world!"); | |
| read_while(isalpha, is2); | |
| } | |
| } | |
| } |
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