ThinkSSL🔒 一键申购 5分钟快速签发 30天无理由退款 购买更放心 广告
## 第5章 语句 ### 5.3.2 case标签必须是整型常量表达式。 ### 5.4.1 - 练习5.14 ```cpp /* 文件名:ex5.14.cpp */ /* C++ Primer中文版第5版, 练习5.14 */ /* 题目要求:从标准输入中读取若干string对象,输出连续重复出现次数最大的单词的出现次数 */ /* 注意事项:在Windows平台上C++文件结束符是Ctrl+Z,且该字符前面不允许有除回车符之外的其他字符 */ #include <string> #include <vector> #include <iostream> using namespace std; int main(void) { vector<string> vStr; string str0, str1, strOut; int num = 1, max = 0; while (cin >> str0) { while (cin >> str1) { if (str0 == str1) { num++; if (max < num) { max = num; strOut = str0; } } else { str0 = str1; num = 1; } } } if (max <= 1) cout << "No duplicated string." << endl; else cout << "The string \"" << strOut << "\" has appeared " << max << " times." << endl; return 0; } ``` ### 5.4.2 - 练习5.17 ```cpp /* 文件名:ex5.17.cpp */ /* C++ Primer中文版第5版, 练习5.17 */ /* 题目要求:从标准输入中读取两组整型序列,判断其中一组序列是否是另一组的前缀 */ /* 注意事项:输入C++文件结束符(Ctrl+Z)之后,应调用输入流成员函数clear()重新激活该输入流对象 */ #include <iostream> #include <vector> using namespace std; bool isPrefix(vector <int> &iv0, vector <int> &iv1) { vector<int> &ivShort = (iv0.size() <= iv1.size()) ? iv0 : iv1; vector<int> &ivLong = (iv0.size() <= iv1.size()) ? iv1 : iv0; for (auto begS = ivShort.begin(), endS = ivShort.end(), begL = ivLong.begin(); begS != endS; ++begS, ++begL) { if (*begS != *begL) return false; } return true; } int main(void) { int i = 0; vector <int> iv0, iv1; //input cout << "Enter a sequence of integers separated by SPACE key: "; for (; cin >> i;) iv0.push_back(i); cin.clear();//更改cin的状态标示符 cin.sync();//清除缓存区的数据流 cout << "Enter another sequence of integers separated by SPACE key: "; for (; cin >> i;) iv1.push_back(i); cin.clear(); cin.sync(); if (isPrefix(iv0, iv1)) cout << "One of the two sequences is the prefix of the other." << endl; else cout << "None of the two sequences is the prefix of the other." << endl; cout << "Enter any key to end..."; cin.get(); return 0; } ``` 参考链接:http://www.cnblogs.com/hubavyn/p/3996413.html ### 5.6.3 - 练习5.24 ```cpp /* 文件名:ex5.24.cpp */ /* C++ Primer中文版第5版, 练习5.24 */ /* 题目要求:不作异常处理,运行时抛出异常的结果 */ #include <iostream> using namespace std; int main(void) { int a = 0, b = 0; cout << "Enter two integers separated by SPACE: "; (cin >> a >> b).sync(); if (0 == b) throw runtime_error("The divisor mustn't be 0."); cout << a << " / " << b << " = " << (a / b) << endl; cout << "Enter any key to end..." << endl; cin.get(); return 0; } ``` 下图为报错截图,运行环境:VS2013,Debug Win32 ![练习5.24程序运行结果截图](https://box.kancloud.cn/162a2bef6c5891f9c7d425c1842d6964_559x355.png =559x355) - 练习5.25 ```cpp /* 文件名:ex5.25.cpp */ /* C++ Primer中文版第5版, 练习5.25 */ /* 题目要求:给练习5.24代码添加异常处理 */ #include <iostream> using namespace std; int main(void) { int a = 0, b = 0; do { cout << "Enter two integers separated by SPACE: "; (cin >> a >> b).sync(); try { if (0 == b) throw runtime_error("The divisor mustn't be 0."); } catch (runtime_error err) { cout << err.what() << "\nTry Again? Enter y or n. "; char c; cin >> c; if (!cin || c == 'n') break; } if (0 != b) break; } while (true); cout << a << " / " << b << " = " << (a / b) << endl; cout << "Enter any key to end..."; cin.get(); return 0; } ``` 实际运行效果(VS2013,Debug Win32): ![练习5.25实际运行截图](https://box.kancloud.cn/cf9e062d25d3fb3b3a294520225ea4e2_442x175.png =442x175)