C++ Primer Plus（第五版）第6章编程题答案

第1题：

//C++ Primer Plus Edition 5
//Chapter 6 Homework 1

#include

#include
using namespace std;
int main() {
cout << “Enter text for analysis and type @”
“to terminate input.\\n”;
char ch;
cin.get(ch);
while (ch != ‘@’) {
if (!isdigit(ch))
{
if (islower(ch))
ch = toupper(ch);
else if (isupper(ch))
ch = tolower(ch);
cout << ch;

    }
    cin.get(ch);
}

system("pause");
return 0;

}
//错误代码，判断如果是数字执行continue的话就会循环判断字符是不是等于@，第一个字符就无限循环。
//else同样。
//while (ch != ‘@’) {
// if (isdigit(ch))
// continue;
// else if (isalpha(ch))
// {
// cout << ch << endl;
// if (islower(ch))
// ch = toupper(ch);
// else if (isupper(ch))
// ch = tolower(ch);
// cout << ch;
// }
// else
// continue;
//}

第2题：

//C++ Primer Plus Edition 5
//Chapter 6 Homework 2

#include

#include
const int SIZE = 10;
using namespace std;
int main() {
double donation[10];
double average;
int countbig = 0;
int count=0;
double sum = 0.0;
cout << “Enter 10 numbers.If you want to quit, just input @:” << endl;
for (int i = 0; i < SIZE; i++) {
cin >> donation[i];
if (cin.fail())
break;
else {
sum += donation[i];
++count;
}
}
average = sum / count;
cout << “The average number is: “ << average << endl;
for (int i = 0; i < count; i++) {
if (donation[i] > average)
++countbig;
}
cout << countbig << “ numbers bigger than average.\\n”;

system("pause");
return 0;

}

第3题：

//C++ Primer Plus Edition 5
//Chapter 6 Homework 3

#include

#include
using namespace std;
void showmenu();
int main() {
showmenu();
char choice;
cin.get(choice);
while ((choice != ‘c’) && (choice != ‘p’) && (choice != ‘t’) && (choice != ‘g’))
{
cout << “Please enter a c,p,t,g: “;
//cin.get(choice);
cin.ignore();
}
switch (choice)
{
case ‘c’:
cout << “This is carnivore’s answer.\\n”;
break;
case ‘p’:
cout << “This is pianist’s answer.\\n”;
break;
case ‘t’:
cout << “A maple is a tree.\\n”;
break;
case ‘g’:
cout << “This is game’s answer.\\n”;
break;
default:
break;
}
system(“pause”);
return 0;
}

void showmenu() {
cout << “Please enter one of the following choices.\\n”
“c)carnivore p)pianist\\n”
“t)tree g)game\\n”;
}

第4题：

//C++ Primer Plus Edition 5
//Chapter 6 Homework 4

#include

#include
using namespace std;
//函数
void showmenu();
void dis_by_name();
void dis_by_title();
void dis_by_bop();
void dis_by_pre();
//定义常量
const int strsize = 30;
const int NUM = 5;
//定义结构体
struct bop {
char fullname[strsize];
char title[strsize];
char bopname[strsize];
int preference;//0=fullname,1=title,2=bopname
};
bop people[5] = {
{
“Wimp Macho”,
“BOSS”,
“WM”,
0
},
{
“Raki Rhodes”,
“Manager”,
“Junior Programmer”,
2
},
{
“Celia Laiter”,
“MIPS”,
“CL”,
1
},
{
“Hoppy Hipman”,
“Analyst Trainee”,
“AT”,
1
},
{
“Pat Hand”,
“Student”,
“LOOPY”,
2
}
};
char ch;
//开始主函数
int main() {
showmenu();
cin >> ch;
while ((ch != ‘a’) && (ch != ‘b’) && (ch != ‘c’) && (ch != ‘d’) && (ch != ‘q’))
{
showmenu();
//cin.get(choice);
cin.ignore();
}
while (ch != ‘q’) {
switch (ch)
{
case ‘a’:
dis_by_name();
break;
case ‘b’:
dis_by_title();
break;
case ‘c’:
dis_by_bop();
break;
case ‘d’:
dis_by_pre();
break;
default:
break;
}
cout << “Next choice:” << endl;
cin >> ch;
while ((ch != ‘a’) && (ch != ‘b’) && (ch != ‘c’) && (ch != ‘d’) && (ch != ‘q’))
{
showmenu();
//cin.get(choice);
cin.ignore();
}

}
cout << "Bye!" << endl;
system("pause");
return 0;

}

void showmenu() {
cout << “Please enter one of the following choices.\\n”
“a)display by name b)display by title\\n”
“c)display by bopname d)display by preference\\n”
“q)game\\n”;
}
void dis_by_name() {
for (int i = 0; i < NUM; ++i)
{
cout << people[i].fullname << endl;
}
}
void dis_by_title() {
for (int i = 0; i < NUM; ++i)
{
cout << people[i].title << endl;
}
}
void dis_by_bop() {
for (int i = 0; i < NUM; ++i)
{
cout << people[i].bopname << endl;
}
}
void dis_by_pre() {
for (int i = 0; i < NUM; ++i) {
if(people[i].preference==0)
cout << people[i].fullname << endl;
else if(people[i].preference==1)
cout<< people[i].title << endl;
else
cout << people[i].bopname << endl;
}
}

第5题：

//C++ Primer Plus Edition 5
//Chapter 6 Homework 5

#include
const double level1 = 0.1;
const double level2 = 0.15;
const double level3 = 0.2;
using namespace std;
int main() {
double tvarp;
double cus;
cout << “Please input your money: “;
cin >> tvarp;
while (cin.good() && (tvarp > 0))
{
if (tvarp <= 5000)
cus = 0.0;
else if (tvarp > 5000 && tvarp <= 15000)
cus = (tvarp - 5000)level1;
else if (tvarp > 15000 && tvarp <= 35000)
cus = 10000 level1 + (tvarp - 15000)level2;
else if (tvarp > 35000)
cus = 10000 level1 + 20000 level2 + (tvarp - 35000)level3;
cout << “您需要交税” << cus << “ tvarp.\\n”;
cout << “Please input your money: “;
cin >> tvarp;
}
cout << “Bye\\n”;

system("pause");
return 0;

}

第6题：

//C++ Primer Plus Edition 5
//Chapter 6 Homework 6

#include

#include
using namespace std;
struct donation
{
string name;
double money;

};
int main() {
int num;
int count = 0;
cout << “Please input the number of donationer: “;
cin >> num;
cin.get();//吃掉换行符
donation donaer = new donation[num];
for (int i = 0; i < num; i++)
{
cout << “Enter the name: “;
getline(cin, donaer[i].name);
cout << “Enter money: “;
cin >> donaer[i].money;
cin.get();//吃掉换行符
}
cout << “**“ << endl;
cout << “Grand Patrons” << endl;
cout << “**“ << endl;
for (int i = 0; i < num; i++) {
if (donaer[i].money > 10000) {
++count;
cout << “Name: “ << donaer[i].name << endl;
cout << “Donate Money: “ << donaer[i].money << endl;
cout << endl;
}
}
if (count == 0)
{
cout << “None” << endl;
}
count = 0;
cout << “**“ << endl;
cout << “Patrons” << endl;
cout << “*“ << endl;
for (int i = 0; i < num; i++) {
if (donaer[i].money <= 10000) {
++count;
cout << “Name: “ << donaer[i].name << endl;
cout << “Donate Money: “ << donaer[i].money << endl;
cout << endl;
}
}
if (count == 0)
{
cout << “None” << endl;
}
delete[] donaer;
system(“pause”);
return 0;
}

第7题：

//C++ Primer Plus Edition 5
//Chapter 6 Homework 7

#include

#include
using namespace std;
int main() {
string word;
char ch;
int yuan = 0;
int fu = 0;
int others = 0;
cin >> word;
while (word != “q”) {
ch = word[0];
if (isalpha(ch))
{
if (ch == ‘a’ || ch == ‘e’ || ch == ‘i’ || ch == ‘o’ || ch == ‘u’
|| ch == ‘A’ || ch == ‘E’ || ch == ‘I’ || ch == ‘O’ || ch == ‘U’)
++yuan;
else
++fu;
}
else
++others;
cin >> word;
}
cout << yuan << “ words beginning with vowels.” << endl;
cout << fu << “ words beginning with consonants.” << endl;
cout << others << “ others.” << endl;

system("pause");
return 0;

}

第8题：

//C++ Primer Plus Edition 5
//Chapter 6 Homework 8

#include

#include
using namespace std;
const int MAXSIZE = 50;
int main() {
char filename[MAXSIZE];
ifstream inFile;
cout << “Please enter the file’s name: “;
cin.getline(filename, MAXSIZE);
inFile.open(filename);
if (!inFile.is_open()) {
cout << “Open this file error.”<<endl;
exit(EXIT_FAILURE);
}
char ch;
int count = 0;
inFile >> ch;
while (inFile.good()) {
++count;
inFile >> ch;
}
if (inFile.eof()) {
cout << “Have reached end of this file.\\n”;
}
else if (inFile.fail()) {
cout << “Input terminated by data mismatch.\\n”;
}
else
cout << “unknown reason to stop.\\n”;
if (count == 0) {
cout << “No data in this file.\\n”;
}
else {
cout << “There are “ << count << “ characters in this file.\\n”;
}
inFile.close();
system(“pause”);
return 0;
}

第9题：

//C++ Primer Plus Edition 5
//Chapter 6 Homework 9

#include

#include
using namespace std;
const int MAXSIZE = 50;
struct donation
{
string name;
double money;

};
int main() {
char filename[MAXSIZE];
ifstream inFile;
cout << “Please enter the file’s name: “;
cin.getline(filename, MAXSIZE);
inFile.open(filename);
if (!inFile.is_open()) {
cout << “Open this file error.” << endl;
exit(EXIT_FAILURE);
}
int num;
int count = 0;
inFile >> num;
inFile.get();//吃掉换行符
donation donaer = new donation[num];
for (int i = 0; i < num; i++)
{
getline(inFile, donaer[i].name);
inFile >> donaer[i].money;
inFile.get();//吃掉换行符
}
cout << “**“ << endl;
cout << “Grand Patrons” << endl;
cout << “**“ << endl;
for (int i = 0; i < num; i++) {
if (donaer[i].money > 10000) {
++count;
cout << “Name: “ << donaer[i].name << endl;
cout << “Donate Money: “ << donaer[i].money << endl;
cout << endl;
}
}
if (count == 0)
{
cout << “None” << endl;
}
count = 0;
cout << “**“ << endl;
cout << “Patrons” << endl;
cout << “*“ << endl;
for (int i = 0; i < num; i++) {
if (donaer[i].money <= 10000) {
++count;
cout << “Name: “ << donaer[i].name << endl;
cout << “Donate Money: “ << donaer[i].money << endl;
cout << endl;
}
}
if (count == 0)
{
cout << “None” << endl;
}
delete[] donaer;
inFile.close();
system(“pause”);
return 0;
}