6-1
有個問題，如果輸入的字符既不是數字也不是字母是不是應該原樣輸出呢？

#include <iostream> #include <cctype>int main() {using namespace std;char ch;cout << "Please enter something.\n";while (cin.get(ch) && ch != '@')if (isalpha(ch)){if (isupper(ch))cout << char(tolower(ch));else if (islower)cout << char(toupper(ch));}else if (!isdigit(ch))cout << ch;return 0; }

6-2
非數值無法cin到double型的donation中，所以停止？

#include <iostream>int main() {using namespace std;double Total[10];cout << "Please enter numbers.(stop with no-numbers)" << endl;int i = 0;double donation;double sum = 0;while (cin >> donation && i < 10){sum += donation;Total[i] = donation;i++;}double average = sum / i;int j = 0;for (int k = 0; k < i; k++){if (Total[k] > average)j++;}cout << "Average is " << average << " and there are " << j << " numbers above the average.\n";return 0; }

6-3

switch本身沒有循環 #include <iostream>int main() {using namespace std;char ch;cout << "Please enter one of the following choice: \n";cout << "c) carnivore p)pianist" << endl;cout << "t) tree g) game" << endl;cin >> ch;while (ch != 'c' && ch != 'p' && ch != 't' && ch != 'g'){cout << "Please enter a c, p, t, of g: ";cin >> ch;}cout << endl;switch (ch){case 'c':cout << "A maple is a carnivore.";break;case'p':cout << "A maple is a pianist.";break;case 't':cout << "A maple is a tree.";break;case 'g':cout << "A maple is a game.";break;default:break;}return 0; }

6-4

#include <iostream> const int strsize = 20; using namespace std; struct bop {char fullname[strsize];char title[strsize];char bopname[strsize];int preference; }; int main() {char PreferType;bop programmers[5] = { {"Wimp Macho", "Analyst Trainee", "WM",0},{"Raki Rhodes", "Junior Programmer", "RR", 1},{"Celia Laiter", "Analyst Trainee", "MIPS", 2},{"Hoppy Hipman", "Analyst Trainee", "HH", 1},{"Pat Hand", "Junior Programmer", "LOOPY", 2} };cout << "Benevolent Order of Programmers Report\n";cout << "a. display by name b. display by title" << endl;cout << "c. display by bopname d. display by preference" << endl;cout << "q. quit" << endl;cout << "Enter your choice: ";while (cin >> PreferType && PreferType != 'q'){switch (PreferType){case 'a':for (int i = 0; i < 5; i++)cout << programmers[i].fullname << endl;cout << "Next choice: ";continue;case 'b':for (int i = 0; i < 5; i++)cout << programmers[i].title << endl;cout << "Next choice: ";continue;case 'c':for (int i = 0; i < 5; i++)cout << programmers[i].bopname << endl;cout << "Next choice: ";continue;case 'd':for (int i = 0; i < 5; i++){if (programmers[i].preference == 0)cout << programmers[i].fullname << endl;else if (programmers[i].preference == 1)cout << programmers[i].title << endl;elsecout << programmers[i].bopname << endl;}cout << "Next choice: ";continue;default:break;}}cout << "Bye!" << endl;return 0; }

6-5
累進稅率

#include <iostream> const int strsize = 20; using namespace std;int main() {cout << "Enter the income: ";double income;while (cin >> income && income > 0){double tax = 0.0;if (income < 5000.0){cout << "tax = 0" << endl;cout << "Enter the income: ";}else if (income < 15000.0){tax += (income - 5000.0) * 0.1;cout << "tax = " << tax << endl;cout << "Enter the income: ";}else if (income < 35000.0){tax += (income - 15000.0) * 0.15;tax += (15000.0 - 5000.0) * 0.1;cout << "tax = " << tax << endl;cout << "Enter the income: ";}else{tax += (income - 35000) * 0.2;tax += (35000.0 - 15000.0) * 0.15;tax += (15000.0 - 5000.0) * 0.1;cout << "tax = " << tax << endl;cout << "Enter the income: ";}}return 0; }

6-6
還是那個問題，用getline之前需要清掉cin數字時留下的空

#include <iostream> #include <string> using namespace std;struct PatronsInfo {string name;double amount; };int main() {int NumOfPatrons;cout << "Enter the number of patrons: ";cin >> NumOfPatrons;cin.get();PatronsInfo* PInfo = new PatronsInfo[NumOfPatrons];for (int i = 0; i < NumOfPatrons; ++i){cout << "\nEnter the name of patrons: ";getline(cin, PInfo[i].name);cout << "\nEnter the amout of patrons: ";cin >> PInfo[i].amount;cin.get();}cout << "Grand Patrons\n";int k = 0;for (int i = 0; i < NumOfPatrons; i++){if (PInfo[i].amount > 10000.0){cout << PInfo[i].name << endl;k++;}}if (k == 0){cout << "None!" << endl;}cout << "Patrons\n";k = 0;for (int i = 0; i < NumOfPatrons; i++){if (PInfo[i].amount <= 10000.0){cout << PInfo[i].name << endl; k++;}}if (k == 0){cout << "None!" << endl;}return 0; }

6-7
判斷是否為元音這么寫太復雜了，看別的博客發現使用find之類的，但是這本書講到這里時也沒有講過這種

#include <iostream> #include <string> using namespace std;int main() {string WordStr;int NumOfVowels, NumOfConsonants, other;NumOfConsonants = NumOfVowels = other = 0;cout << "Enter words (q to quit): \n";while (cin >> WordStr && WordStr != "q"){if (!isalpha(WordStr[0]))other += 1;else if (WordStr[0] == 'A' or WordStr[0] == 'E' or WordStr[0] == 'I' or WordStr[0] == 'O' or WordStr[0] == 'U' or WordStr[0] == 'a' or WordStr[0] == 'e' or WordStr[0] == 'i' or WordStr[0] == 'o' or WordStr[0] == 'u')NumOfVowels += 1;else if (isalpha)NumOfConsonants += 1;}cout << NumOfVowels << " words begining with vowels\n";cout << NumOfConsonants << " words begining with consonants\n";cout << other << " others\n";return 0; }

6-8

#include <iostream> #include <fstream> using namespace std;int main() {ifstream txtfile;txtfile.open("D://test.txt");if (!txtfile.is_open()){cout << "Failed to open file!" << endl;exit(EXIT_FAILURE);}char ch;int count = 0;while (txtfile >> ch)count++;if (txtfile.eof())cout << "End of file reached.\n";else if (txtfile.fail())cout << "Input termiated by data mismatch.\n";elsecout << "Input terminated for unknown reason.\n";if (count == 0)cout << "No data processed.\n";elsecout << "There are " << count << " characters in this file." << endl;return 0; }

6-9
出現了一個錯誤，string是std里面的，需要聲明，或者把using namespace std寫在前面

#include <iostream> #include <fstream> #include <string>struct PatronsInfo {std::string name;double amount; };int main() {using namespace std;ifstream txtfile;txtfile.open("D://test.txt");if (!txtfile.is_open()){cout << "Failed to open file!" << endl;exit(EXIT_FAILURE);}int NumOfPatrons;(txtfile >> NumOfPatrons).get();PatronsInfo* PInfo = new PatronsInfo[NumOfPatrons];for (int i = 0; i < NumOfPatrons; i++){txtfile >> PInfo[i].name;txtfile >> PInfo[i].amount;}cout << "Grand Patrons\n";int k = 0;for (int i = 0; i < NumOfPatrons; i++){if (PInfo[i].amount > 10000.0){cout << PInfo[i].name << endl;k++;}}if (k == 0){cout << "None!" << endl;}cout << "Patrons\n";k = 0;for (int i = 0; i < NumOfPatrons; i++){if (PInfo[i].amount <= 10000.0){cout << PInfo[i].name << endl;k++;}}if (k == 0){cout << "None!" << endl;}return 0; }

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