第六章習題——C++ Primer Plus
這是一個寫作業的系列,旨在po出執行通過的程式碼。前五章較為簡單,於是沒有寫。從第六章開始,我會完成這一系列的作業。提高自己coding的熟練度。
編譯環境:Visual Sudio 2017
1. 編寫一個程式,讀取鍵盤輸入,直到遇到@符號為止,並回顯輸入(數字除外),同時將大寫字元轉換為小寫,將小寫字元轉換為大寫(別忘了cctype函式系列)。
//6.1 #include "stdafx.h"//膝上型電腦在VS執行時應該首先加入這個標頭檔案,否則iostream無法工作 #include <iostream> #include <cctype> using namespace std; int main() { cout << "Enter data until an @ to terminate the input.\n"; char ch; while (cin.get(ch) && ch != '@') { if (ch >= 'a'&&ch <= 'z') ch = toupper(ch); else if (ch >= 'A'&&ch <= 'Z') ch = tolower(ch); cout << ch; } cout << "\nInput complete.\n"; system("pause"); return 0; }
2. 編寫一個程式,最多將10個donation值讀入到一個double陣列中。程式遇到非數字輸入時將結束輸入,並報告這些數字的平均值以及陣列中有多少個數字大於平均值。
#include "stdafx.h" #include<iostream> #include<array> using namespace std; int main() { //double arr[10];//可以選擇使用陣列 array<double, 10>arr; int i = 0, j, num; double sum = 0, average = 0,temp; cout << "輸入最多10個donation值:(非數字時將結束輸入)\n"; while ((cin >> temp) && (i<10)) { arr[i] = temp; sum += arr[i++]; } average = sum / i; for (j = 0, num = 0; j < i; j++) { if (arr[j] > average) num++; } cout << "平均值:" << average<< " ,有 "<< num<< " 個數字超過平均值"<< endl; system("pause"); return 0; }
3.編寫一個選單驅動程式的雛形。該程式顯示一個提供4個選項的選單——每個選項用一個字母標記。
#include "stdafx.h" #include <iostream> using namespace std; int main() { char ch; cout << "Please enter one of the following choices:\n"; cout << "c)carnivore\t" << "p) pianist"<<endl; cout << "t)tree\t\t" << "g) game"<<endl; while (cin >> ch) { switch (ch) { case 'c': cout << "Danger!\n"; break; case 'p': cout << "Enjoy the music.\n"; break; case 't': cout << "A maple is a tree.\n"; break; case 'g': cout << "No child don't love game!\n"; break; default: cout << "Please enter a c, p, t, or g:"; continue; } } system("pause"); return 0; }
4. 加入Benevolent Order of Programmer後,在BOP大會上,人們便可以通過加入者的真實姓名、頭銜或祕密BOP姓名來了解他(她)。請編寫一個程式,可以使用真實姓名、頭銜、祕密姓名或成員偏好來列出成員。
#include "stdafx.h"
#include <iostream>
const int strsize = 30;
struct bop{
char fullname[strsize];
char title[strsize];
char bopname[strsize];
char preference[strsize];
};
using namespace std;
int main()
{
bop information[5]{
{"Wimp Macho","Professor","W.M","Wimp Macho" },
{"Raki Rhodes", "Engineer", "Chock", "Junior Programmer" },
{"Celia Laiter","Associate professor","Great C","MIPS"},
{"Hoppy Hipman","Lecturer","HipHop","Analyst Trainee"},
{ "Pat Hand","Student","RatCat","LOOPY"},
};
char ch;
int i;
cout << "a. diplay by name\t" << "b. display by title" << endl;
cout << "c. display by bopname\t" << "d. display by preference" << endl;
cout << "q. quit" << endl;
cout << "Enter your choice:" ;
while (cin>>ch&&ch != 'q')
{
switch(ch)
{
case 'a':
for (i = 0; i < 5; i++)
{
cout << information[i].fullname << endl;
}
break;
case 'b':
for (i = 0; i < 5; i++)
{
cout << information[i].title << endl;
}
break;
case 'c':
for (i = 0; i < 5; i++)
{
cout << information[i].bopname << endl;
}
break;
case 'd':
for (i = 0; i < 5; i++)
{
cout << information[i].preference << endl;
}
break;
default:
cout << "Please recheck your input." << endl;
cout << "Enter your choice(a,b,c,d,q)";
continue;
}
cout << "Next choice:";
}
system("pause");
return 0;
}
5. 在Neutronia王國,貨幣單位是tvarp,收入所得稅的計算方式如下:
5000 tvarps”:不收稅
5001~15000 tvarps:10%
15001~35000 tvarps:15%
35000以上: 20%
例如,收入為38000 tvarps時,所得稅為5000*0.00 + 10000*0.10+20000*0.15+3000*0.20,即4600tvarps。請編寫一個程式,使用迴圈來要求使用者輸入收入,並報告所得稅。當用戶輸入負數或非數字時,迴圈將結束。
寫這題的程式碼時,我將不同的納稅區間定義成了常量,便於程式的修改。
#include "stdafx.h"
#include <iostream>
const int line1 = 5000;//第一條徵稅線
const int line2 = 15000;//第二條徵稅線
const int line3 = 35000;//第一條徵稅線
const int step1 = line1; //第一徵稅區間
const int step2 = line2 - line1;//第一徵稅區間
const int step3 = line3 - line2;//第三徵稅區間
const float rate1 = 0.00; //第一徵稅區間稅率
const float rate2 = 0.10; //第二徵稅區間稅率
const float rate3 = 0.15; //第三徵稅區間稅率
const float rate4 = 0.20; //第四徵稅區間稅率
using namespace std;
int main()
{
int income;
float tax = 0;
cout << "請輸入您的收入:";
while (cin >> income&&income >= 0)
{
if (income > step1)
{
tax += step1*rate1;
income -= step1;
if (income > step2)
{
tax += step2*rate2;
income -= step2;
if (income > step3)
{
tax += step3*rate3;
income -= step3;
if (income > 0)
tax += income*rate4;
}
else tax += income*rate3;
}
else tax += income*rate2;
}
else tax += income*rate1;
cout << "經計算,您所需要繳納稅款為" << tax << "tvarps。\n";
cout << "請輸入您的收入:";
}
return 0;
}
6.6 編寫一個程式,記錄捐助給“維護合法權利團體”的資金。該程式要求使用者輸入捐獻者數目,然後要求使用者輸入每一個捐獻者的姓名和款項。這些資訊被儲存在一個動態分配的結構陣列中。每個結構有兩個成員:用於儲存姓名的字元陣列(或string物件)和用來儲存款項的double成員。讀取所有的資料後,程式將顯示所有捐款超過10000的捐款者姓名及其捐款數額。該列表前包含一個標題,指出下面的捐款者是重要捐款人(Grand Patrons)。然後,程式將列出其他的捐款者,該列表要以Patrons開頭。如果某種類別沒有捐款者,則程式將列印單詞“none”。該程式只顯示這兩種類別,而不進行排序。
#include "stdafx.h"
#include <string>
#include <iostream>
using namespace std;
struct fundrecord
{
string Name;
double Money;
};
int main()
{
unsigned int num;
int i,flag;
cout << "'維護合法權利團體'資金記錄" << endl;
cout << "捐獻者人數:";
while (!(cin >> num))
{
cin.clear();
cin.get();
cout<<"請檢查輸入,它必須是一個正整數。\n";
cout << "捐獻者人數:";
}
fundrecord *ps = new fundrecord[num];
for(i =0;i<num;i++)
{
cout << "第" << i + 1 << "個捐獻者記錄:\n";
cout << "姓名:";
cin >> ps[i].Name;
cout << "款項:";
cin >> ps[i].Money;
}
flag = 0;
cout << "\nGrand Patrons:" << endl;
for(i=0;i<num;i++)
{
if(ps[i].Money>10000)
{
flag++;
cout << ps[i].Name << ",\t$" << ps[i].Money <<"\n\n";
}
}
if (flag == 0)
cout << "None\n\n";
flag=0;
cout << "Patrons:" << endl;
for (i = 0; i<num; i++)
{
if (ps[i].Money<=10000)
{
flag++;
cout << ps[i].Name << ",\t$" << ps[i].Money <<"\n\n";
}
}
if (flag == 0)
cout << "None\n\n" ;
delete [] ps;
system("pause");
return 0;
}
6.7 編寫一個程式,它每次讀取一個單詞,直到使用者只輸入q。然後,該程式指出有多少個單詞以母音打頭,有多少個單詞以子音打頭,還有多少個單詞不屬於這兩類。為此,方法之一是,使用isalpha()來區分以字母和其他字元打頭的單詞,然後對於通過isalpha()測試的單詞,使用if或switch語句來確定哪些以母音打頭。
#include "stdafx.h"
#include <iostream>
#include<string>
using namespace std;
const int ArSize = 10;
bool isvowels(char);
int main()
{
string word;
char ch;
int i = 0,j = 0, k = 0;//i個母音,j個子音,k個其他
cout<<"Enter words (q to quit):\n";
cin >> word;
while (word != "q")
{
ch = word[0];
if (!isalpha(ch))
k++;
else
if (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u'||
ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U')
i++;
else
j++;
cin >> word;
}
cout << i << " words beginning with vowels.\n";
cout << j << " words beginning with consonants.\n";
cout << k << " others.\n";
system("pause");
return 0;
}
6.8 編寫一個程式,它開啟一個文字檔案,逐個字元地讀取該檔案,直到到達檔案末尾,然後指出該檔案中包含多少個字元。
我這裡還有一個沒有解決的問題:打不開絕對路徑的檔案。太奇怪了。
使用除錯模式的話,開啟的檔案1.txt要放在.vcxproj同一個資料夾下;使用exe執行的話,開啟的檔案1.txt要放在exe同一個資料夾下。
#include "stdafx.h"
#include<iostream>
#include<fstream>
using namespace std;
int main()
{
//char filename[SIZE];
//ofstream outFile;
//outFile.open("1.txt");
ifstream inFile;
//cout << "Enter name of data file: ";
//cin.getline(filename, SIZE);
inFile.open("1.txt");
if (!inFile.is_open())
{
cout << "Could not open the file:"<<endl;//<< filename << endl;
cout << "Program terminating.\n";
system("pause");
exit(EXIT_FAILURE);
}
char zifu;
int count=0;//讀取有多少個字元
inFile >> zifu;
while (inFile.good())
{
++count;
inFile >> zifu;
}
if (inFile.eof())
cout << "End of file reached.\n";
else if (inFile.fail())
cout << "Input terminated by data mismatch.\n";
else cout << "Input terminated by unknown reason.\n";
if (count == 0)
cout << "No data processed.\n";
else
cout << "檔案中有" << count << "個字元。\n";
inFile.close();
system("pause");
return 0;
}
6.9 完成程式設計練習6,但從檔案中讀取所需的資訊。該檔案的第一項應為捐款人數,餘下的內容應為成對的行。在每一對中,第一行為捐款人姓名,第二行為捐款數額。即該檔案類似於下面:
4
Sam Stone
2000
Freida Flass
100500
Tammy Tubbs
5000
Rich Raptor
55000
// 66.cpp: 定義控制檯應用程式的入口點。
//
#include "stdafx.h"
#include <string>
#include<fstream>
#include <iostream>
using namespace std;
struct fundrecord
{
string Name;
double Money;
};
int main()
{
//開啟檔案
ifstream inFile;
inFile.open("list.txt");
if (!inFile.is_open())
{
cout << "Could not open the file:" << endl;
cout << "Program terminating.\n";
system("pause");
exit(EXIT_FAILURE);
}
//處理資料
unsigned int num;
int i, flag;
cout << "'維護合法權利團體'資金記錄" << endl;
cout << "捐獻者人數:";
inFile >> num;
cout << num<<endl;
fundrecord *ps = new fundrecord[num];
inFile.get();//注意新增這一項接收回車\n
for (i = 0; i<num; i++)
{
cout << "第" << i + 1 << "個捐獻者記錄:\n";
cout << "姓名:";
getline(inFile,ps[i].Name);
cout << ps[i].Name<<"\t";
cout << "款項:";
inFile >> ps[i].Money;
cout<< ps[i].Money<<endl;
inFile.get();
}
flag = 0;
cout << "\nGrand Patrons:" << endl;
for (i = 0; i<num; i++)
{
if (ps[i].Money>10000)
{
flag++;
cout << ps[i].Name << ",\t$" << ps[i].Money << "\n\n";
}
}
if (flag == 0)
cout << "None\n\n";
flag = 0;
cout << "Patrons:" << endl;
for (i = 0; i<num; i++)
{
if (ps[i].Money <= 10000)
{
flag++;
cout << ps[i].Name << ",\t$" << ps[i].Money << "\n\n";
}
}
if (flag == 0)
cout << "None\n\n";
delete[] ps;
if (inFile.eof())
cout << "End of file reached.\n";
else if (inFile.fail())
cout << "Input terminated by data mismatch.\n";
else cout << "Input terminated by unknown reason.\n";
inFile.close();
system("pause");
return 0;
}