C++primer 9.5.3节练习

练习9.47

 1 #include<iostream>
 2 #include<vector>
 3 #include<list>
 4 #include <string>
 5 #include <cstring>
 6 
 7 using namespace std;
 8 
 9 int main()
10 {
11     string str{ "ab2c3d7R4E6" };
12     string num{ "0123456789" };
13     string::size_type pos = 0;
14     string::size_type pos1 = 0;
15     while ((pos = str.find_first_of(num, pos)) != string::npos)
16     {
17         cout << pos << endl;
18         ++pos;
19     }
20     while ((pos1 = str.find_first_not_of(num, pos1)) != string::npos)
21     {
22         cout << pos1 << endl;
23         ++pos1;
24     }
25     system("pause");
26     return 0;
27 }

练习9.48

返回string::npos;

练习9.49

 1 #include<iostream>
 2 #include<string>
 3 #include<fstream>
 4 
 5 using std::string;using std::ifstream;using std::endl;using std::cout;
 6 
 7 int main()
 8 {
 9     ifstream ifs("title.txt");
10     if (!ifs)
11         return -1;
12 
13     string longest_word;
14     for (string word; ifs >> word; )
15         if (word.find_first_not_of("aceimnorsuvwxz") == string::npos &&
16             word.size()>longest_word.size())
17             longest_word = word;
18     cout << longest_word << endl;
19 
20     ifs.close();
21 
22     system("pause");
23     return 0;
24 }

 

posted @ 2017-08-11 20:17  五月份小姐  阅读(128)  评论(0)  编辑  收藏  举报