C++ Primer Plus第六版第六章程式設計練習答案
阿新 • • 發佈：2018-11-17
6.1
#include<stdafx.h> #include<iostream> #include<cctype> int main() { using namespace std; char ch; cout << "enter characters<end in @>:"; while ((ch=cin.get())!='@')//測試條件不能為(cin>>ch)!='@',cin返回值為cin物件、或者在需要bool型別的地方返回bool值;帶引數的cin.get(ch)函式返回值也為流物件；只有不帶引數的cin.get()函式返回值為int型 { if (isdigit(ch)) continue; else { cout << "the charicter is: " << ch<<endl; if (islower(ch)) cout << "It's upper case is " << char(toupper(ch)) << endl;//將toupper返回值強制轉換為char用於輸出該字元 else if (isupper(ch)) cout << "It's lower case is: " << char(tolower(ch))<< endl; else continue; } } return 0; }
6.2
#include<stdafx.h> #include<iostream> const int SIZE = 10; int main() { using namespace std; double donation[SIZE]; double sum = 0; double aver; cout << "enter numbers<at most ten and end with a non-number>: " << endl; int count = 0; while (count<10&&(cin>>donation[count])) { sum += donation[count]; ++count; } aver = sum / count; cout << "you total enter " << count << "numbers.\n" << "the average is: " << aver; return 0; }
6.3
#include<stdafx.h> #include<iostream> using namespace std; int main() { char ch; cout << "Please enter one of the following choices:\n" << "c) carnivore P) pianist\n" << "t) tress g) game\n"; bool wrong = false;//用於控制迴圈，當輸入不正確的重新輸入並判斷 while (cin>>ch&&!wrong)//當輸入正確才會結束迴圈 { switch (ch) { case 'c': case'C ': cout << "A maple is a carnivore."; wrong = true;//輸入正確控制while迴圈結束 break;//switch開關語句不加break會按順序執行每條語句，因此在每種情況有多條語句時也不用加大括號 case 'p': case'P': cout << "A maple is a pianist."; wrong = true; break; case't': case'T': cout << "A maple is a tress."; wrong = true; break; case'g': case'G': cout << "A maple is a game."; wrong = true; break; default: cout << "Please enter a c, p, t, or g: "; wrong = false;//輸入錯誤再次執行while語句 break; } } return 0; }
6.4
#include<stdafx.h>
#include<iostream>
#include<iomanip>
const int strsize = 20;
const int number = 5;//存放人員數
using namespace std;
struct bop
{
char fullname[strsize];
char title[strsize];
char bopname[strsize];
int perference;
};
int main()
{
bop list[number] =
{
{"Wimp Macho","Senior programmer","WM",0},
{"Raki Rhodes","Junior programmer","RR",1},
{"Celia Laiter","Analyst ","MIPS",2},
{"Hoppy Hipman","Analyst Trainee","HHi",1},
{"Pat Hand","Juior programmer","LOOPY",2}
};
char ch;
cout << "Benevolent Order of Programmers Report\n";
cout.flags(ios::left);//設定輸出左對齊（預設為右對齊）
cout << setw(25) << "a.display by name" << "b.display by title\n";//sew()用於設定其後的每個輸出所佔的位元組寬度，僅對緊跟其後的一個輸出有效，這裡只對a選項有效佔25位元組
cout<<setw(25) << "c.display by bopname" << "d.display by preference\n";
cout << "q.quite\n";
cout << "enter your choice: ";
cin >> ch;
while (ch!='q')
{
if (ch == 'a')
for (int i = 0; i < number; i++)
{
cout << list[i].fullname << endl;
}
else if (ch == 'b')
for (int i = 0; i < number; i++)
{
cout << list[i].title << endl;
}
else if (ch == 'c')
for (int i = 0; i < number; i++)
{
cout << list[i].bopname;
}
else if (ch == 'd')
{
for (int i = 0; i < number; i++)
{
switch (list[i].perference)
{
case 0:cout << list[i].fullname << endl; break;
case 1:cout << list[i].title << endl; break;
case 2:cout << list[i].bopname << endl; break;
}
}
}
else
{
cout << "Please enter a,b,c,d or q: ";
cin >> ch;
break;
}
cout << "next choice: ";
cin >> ch;
}
cout << "Bye";
return 0;
}
6.5
#include<stdafx.h>
#include<iostream>
#include<iomanip>
const double tax_rate1 = 0.1;
const double tax_rate2 = 0.15;
const double tax_rate3 = 0.2;
using namespace std;
int main()
{
int income;
double tax ;
cout << "enter your income: ";
while (cin>>income&&income>0)//當輸入補位數字時cin>>income返回false
{
if (income <= 5000)
tax = 0;
else if (income > 5000 && income <= 15000)
tax = (income - 5000)*tax_rate1;
else if (income > 1500 && income <= 3500)
tax = 1000 * tax_rate1 + (income - 1500)*tax_rate2;
else
tax = 1000 * tax_rate1 + 2000 * tax_rate2 + (income - 3500)*tax_rate3;
cout << "your income tax is: " << tax<<endl;
cout << "enter your income: ";
}
return 0;
}
6.6
#include<stdafx.h>
#include<iostream>
#include<string>
using namespace std;//定義名稱空間要在結構體之前否則不能識別string，系統將不會將其視為結構體的成員之一
struct donar
{
string name;
double money;
};
int main()
{
int number;
int G_patr=0;
int patr=0;
cout << "Please enter the naumber of donars:";
cin >> number;
donar *P = new donar[number];
cout << "Please enter the message of each donar.\n";
for (int i = 0; i < number; i++)
{
cout << "name #"<<i+1<<": ";
cin.get();//前面輸入過數字，換行符還存在緩衝區中，不將其吸收將影響下面輸入字元
getline(cin,(P+i)->name);//cin不能輸入多個單詞
cout << "money #" << i + 1 << ": ";
cin >> (P + i)->money;
}
cout << "Grand Patrons:\n";
for (int i = 0; i < number; i++)
{
if ((P+i)->money>10000)
{
++G_patr;
cout << (P + i)->name << endl;
}
}
if (!G_patr)
cout << "none\n";
cout << "Patrions:\n";
for (int i = 0; i < number; i++)
{
if ((P + i)->money <10000)
{
++patr;
cout << (P + i)->name << endl;
}
}
if (!patr)
cout << "none\n";
return 0;
}
6.7
#include<stdafx.h>
#include<iostream>
#include<string>
using namespace std;
int main()
{
string word;
int vowel = 0;
int cons = 0;
int others = 0;
cout << "enter words<end in q>: \n";
cin >> word;
while (word!="q")//不能直接用word！=‘q’為測試條件，word時string類類似於字串，而‘q’是字元；
{
if (isalpha(word[0]))//cctype函式引數為字元而不是字串不能用word
{
if (word[0] == 'a' || word[0] == 'e' || word[0] == 'i' || word[0] == 'o' || word[0] == 'u')
++vowel;
else
++cons;
}
else
++others;
cin >> word;//不加此條語句word的值將一直是輸入的第一個單詞，其他的單詞將留在緩衝佇列裡面，且輸入換行符以後將不能再輸入
}
cout << vowel << " words beginning with vowels\n"
<< cons << " words beginning with consonants\n"
<< others << " others";
return 0;
}
6.8
/*首先需要在可執行檔案所在的資料夾中建立一個名為scores的文字檔案，
並輸入資料*/
#include<stdafx.h>
#include<iostream>
#include<fstream>
#include<cstdlib>
using namespace std;
int main()
{
double number;
int count = 0;
ifstream inFile;
inFile.open("scores.txt");
if (!inFile.is_open())
{
cout << "can't opent the file!\n";
exit(EXIT_FAILURE);
}
inFile >> number;
while (inFile.good())
{
++count;
inFile >> number;
}
if (inFile.eof())
cout << "Reach the end of file.\n";
else if (inFile.fail())
cout << "Input terminated by data mismatch.\n";
else
cout << "Input terminated for unknown reason.\n";
cout << "Iteams read " << count;
return 0;
}
6.9
#include<stdafx.h>
#include<iostream>
#include<fstream>
#include<cstdlib>
#include<string>
using namespace std;
struct donar
{
string name;
double money;
};
int main()
{
double number;
int G_patr= 0;
int patr = 0;
ifstream inFile;
inFile.open("mesage.txt");
if (!inFile.is_open())
{
cout << "can't opent the file!\n";
exit(EXIT_FAILURE);
}
inFile >> number;
donar *p = new donar[number];
for (int i = 0; i < number&&inFile.good(); i++)
{
inFile.get();//數字和字元的混合輸入，檔案中數字和字元中間有換行符，不將其吸收將不能正確輸入名字
getline(inFile,(p+i)->name);//名字由多個單片語成，不能直接用inFile>>只能將一次單詞讀入，原理同cin
inFile >> (p+i)->money;
}
if (inFile.eof())//檢查是否輸入完成全部資料
cout << "Reach the end of file.\n";
else if (inFile.fail())
cout << "Input terminated by data mismatch.\n";
else
cout << "Input terminated for unknown reason.\n";
cout << "Grand Patrons:\n";
for (int i = 0; i < number; i++)
{
if ((p + i)->money > 10000)
{
++G_patr;
cout << (p + i)->name<<endl;
}
}
if (G_patr == 0)
cout << "none\n";
cout << "Patrons:\n";
for (int i = 0; i < number; i++)
{
if ((p + i)->money <=10000)
{
++patr;
cout << (p + i)->name << endl;
}
}
if (patr == 0)
cout << "none\n";
return 0;
}