C++ Primer Plus 课后编程练习——第六章分支语句和逻辑运算符

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最新推荐文章于 2023-08-21 17:19:34 发布

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分类专栏： C/C++ 文章标签： C++ Primer Plus 编程练习第六章分支语句

本文链接：https://blog.youkuaiyun.com/john_bian/article/details/78398187

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本文提供了多个C++编程实例，涵盖字符处理、数组操作、菜单驱动程序、数据输入验证、文件处理等方面，帮助读者掌握C++的基本语法和常用编程技巧。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

1、编写一个程序，读取键盘输入，直到遇到@符号为止，并回显输入（数字除外），同时将大写字符转换成小写，将小写字符转换成大写。

#include<iostream>
#include<cctype>
using namespace std;

int main(){
	char c;
	cin >> c;
	while (c != '@'){
		if (islower(c)){
			c = toupper(c);
		}
		else if (isupper(c)){
			c = tolower(c);
		}
		cout << c << endl;
		cin >> c;
	}
	return 0;
}

2、编写一个程序，最多将10个donation值读入到一个double数组中（如果您愿意，也可以使用模板类array）。程序遇到非数字输入时结束输入，并报告这些数字的平均值以及数组中有多少个数字大于平均值。

#include<iostream>
#include<cctype>
using namespace std;

int main(){
	double donation[10];
	int num = 0;
	double sum = 0;
	
	for (int i = 0; i < 10; i++){
		if (cin >> donation[i]){
			num++;
			sum += donation[i];
		}
		else{
			break;
		}		
	}

	if (num != 0){
		double average = sum / num;
		int bigger = 0;
		for (int i = 0; i < num; i++){
			if (donation[i]>average)
				bigger++;
		}
		cout << "平均值为： " << average << "\t共有" << bigger << " 个数比平均值大" << endl;
	}
	
	return 0;
}

3、编写一个菜单驱动程序的雏形。该程序显示一个提供4个选项的菜单——每个选项用一个字母标记。如果用户使用有效选项之外的字母进行响应，程序提示用户输入一个有效的字母，直到用户这样做为止，然后，该程序使用一条switch语句，根据用户的选择执行一个简单的操作。

#include<iostream>
using namespace std;

int main(){
	cout << "Please enter one of the following choices:" << endl;
	cout << "c) carnivore \t p) pianist" << endl;
	cout << "t) tree \t g) game" << endl;
	char in;
	cin >> in;
	bool finish = false;

	while (!finish){
		switch (in){
		case 'c':
			cout << "A maple is a carnivore." << endl;
			finish = true;
			break;
		case 'p':
			cout << "A maple is a pianist." << endl;
			finish = true;
			break;
		case 't':
			cout << "A maple is a tree." << endl;
			finish = true;
			break;
		case 'g':
			cout << "A maple is a game." << endl;
			finish = true;
			break;
		default:
			cout << "Please enter c , p , t or g : ";
			cin >> in;
		}
	}
	return 0;
}

4、加入Benevolent Order of Programmer后，在BOP大会上，人们便可以通过加入者的真实姓名、头衔、秘密姓名或成员偏好来列出成员。/*题目过长，详见人民邮电出版社出版的《C++ Primer Plus》第六版中文版第200页*/

#include<iostream>
using namespace std;

const int strsize = 25;
const int num = 5;

struct bop{
	char fullname[strsize];
	char title[strsize];
	char bopname[strsize];
	int preference;
};

int main(){

	bop peoples[num] = {
		{ "曹操", "丞相", "孟德",1 },
		{ "刘备", "汉中王", "玄德",0 },
		{ "关羽", "汉寿亭侯", "云长",1 },
		{ "赵云", "顺平侯", "子龙",2 },
		{ "周瑜", "将军", "公瑾",2 }
	};

	cout << "Benevolent Order of Programmers Report" << endl;
	cout << "a. display 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: ";

	char c;
	cin >> c;
	bool finish = false;

	while (!finish){
		switch (c){
		case 'a':
			for (int i = 0; i < num; i++){
				cout << peoples[i].fullname << endl;
			}
			cout << "Next choice: ";
			cin >> c;
			break;
		case 'b':
			for (int i = 0; i < num; i++){
				cout << peoples[i].title << endl;
			}
			cout << "Next choice: ";
			cin >> c;
			break;
		case 'c':
			for (int i = 0; i < num; i++){
				cout << peoples[i].bopname << endl;
			}
			cout << "Next choice: ";
			cin >> c;
			break;
		case 'd':
			for (int i = 0; i < num; i++){
				switch (peoples[i].preference){
				case 0:
					cout << peoples[i].fullname << endl;
					break;
				case 1:
					cout << peoples[i].title << endl;
					break;
				case 2:
					cout << peoples[i].bopname << endl;
					break;
				}
			}
			cout << "Next choice: ";
			cin >> c;
			break;
		case 'q':
			cout << "Bye!" << endl;
			finish = true;
			break;
		default:
			cout << "Next choice: ";
			cin >> c;
			break;
		}
	}

	return 0;
}

5、在Neutronia王国，货币单位是tvarp，收入所得税的计算方式如下：

5000tvarp：不收税

5001——15000tvarp： 10%

15001——35000tvarp： 15%

35000tvarp以上： 20%

请编写一个程序，使用循环来要求用户输入收入，并报告所得税。当用户输入负数或非数字时，循环将结束。

#include<iostream>
using namespace std;

int main(){
	double salary;
	cout << "请输入工资： ";

	while (cin >> salary){
		if (salary < 0){
			break;
		}

		double tax = 0;
		if (salary>5000){
			tax += (salary - 5000)*0.1;
			if (salary > 15000){
				tax += (salary - 15000)*0.05;
				if (salary > 35000){
					tax += (salary - 35000)*0.05;
				}
			}
		}
		cout << "应交税费： " << tax << " tvarp" << endl;
		cout << "请输入工资： ";
	}

	return 0;
}

6、编写一个程序，记录捐助给“维护合法权利团体”的资金。该程序要求用户输入捐献者数目，然后要求用户输入每一个捐献者的姓名和款项。这些信息被储存在一个动态分配的结构数组中。每个结构有两个成员：用来存储姓名的字符数组（或string对象）和用来存储款项的double成员。读取所有的数据后，程序将显示所有捐款超过10000的捐款者姓名及捐款数额。该列表前应包含一个标题，指出下面的捐款者是重要捐款人（GrandPatrons）。然后，程序列出其他的捐款者，该列表要以Patron开头。如果某种类别没有捐款者，则程序将打印单词“none”。该程序只显示这两种类别，而不进行排序。

#include<iostream>
#include<string>
using namespace std;

struct donation{
	string name;
	double money;
};

int main(){
	int num;
	cout << "Please enter the number of donors: ";
	cin >> num;
	donation *d = new donation[num];
	int bigger = 0;
	
	for (int i = 0; i < num; i++){
		cout << "Please enter the name and money:" << endl;
		cin >> d[i].name;
		cin >> d[i].money;
		if (d[i].money>10000){
			bigger++;
		}
	}

	if (bigger > 0 && bigger < num){
		cout << "Grand Patrons" << endl;
		for (int i = 0; i < num; i++){
			if (d[i].money>10000){
				cout << d[i].name << "\t" << d[i].money << endl;
			}
		}
		cout << "Patrons" << endl;
		for (int i = 0; i < num; i++){
			if (d[i].money <= 10000){
				cout << d[i].name << "\t" << d[i].money << endl;
			}
		}
		return 0;
	}

	if (bigger == 0){
		cout << "Grand Patrons" << endl;
		cout << "none" << endl;
		cout << "Patrons" << endl;
		for (int i = 0; i < num; i++){
			if (d[i].money <= 10000){
				cout << d[i].name << "\t" << d[i].money << endl;
			}
		}
		return 0;
	}

	if (bigger == num){
		cout << "Grand Patrons" << endl;
		for (int i = 0; i < num; i++){
			if (d[i].money>10000){
				cout << d[i].name << "\t" << d[i].money << endl;
			}
		}
		cout << "Patrons" << endl;
		cout << "none" << endl;
	}
delete[]d;
	return 0;
}

7、编写一个程序，它每次读取一个单词，直到用户只输入q。然后，该程序指出有多少个单词以元音大头，有多少个单词以辅音打头，还有多少单词不属于这两类。为此，方法之一是，使用isalpha()来区分以字母和其他字符打头的单词，然后对于通过了isalpha()测试的单词，使用if或switch语句来确定哪些以元音打头。

#include<iostream>
#include<string>
#include<cctype>
using namespace std;

int main(){

	string str;
	int kind1 = 0;//元音开头
	int kind2 = 0;//辅音开头
	int kind3 = 0;//其他开头
	
	cout << "Enter words (q to quit):" << endl;
	cin >> str;

	while (str != "q"){
		if (isalpha(str[0])){
			if (str[0] == 'a' || str[0] == 'A' || str[0] == 'o' || str[0] == 'O'
				|| str[0] == 'e' || str[0] == 'E' || str[0] == 'i' || str[0] == 'I'
				|| str[0] == 'u' || str[0] == 'U'){
				kind1++;
			}
			else{
				kind2++;
			}
		}
		else{
			kind3++;
		}
		cin >> str;
	}

	cout << kind1 << " words beginning with vowels" << endl;
	cout << kind2 << " words beginning with consonants" << endl;
	cout << kind3 << " others" << endl;

	return 0;
}

8、编写一个程序，它打开一个文件，逐个字符地读取该文件，直到到达文件末尾，然后指出该文件中包含多少个字符。

#include<iostream>
#include<fstream>
using namespace std;

int main(){

	char c;
	long num = 0;

	ifstream read;
	read.open("F:\\Wine.txt");

	while (read >> c){
		num++;
	}
	cout << "文件中共有 " << num << " 个字符" << endl;
	return 0;
}

9、完成编程练习6，但从文件中读取所需的信息。该文件的第一项应为捐款人数，余下的内容应为成对的行。在每一对中，第一行为捐款人姓名，第二行为捐款数额。

#include<iostream>
#include<fstream>
#include<string>
 
using namespace std;
 
struct donation{
char name[30];
double money;
};
 
int main(){
 
ifstream read;
read.open("F:\\donation.txt");
 
int num;
read >> num;
char str[30];
read.getline(str,1);
donation *d = newdonation[num];
int bigger = 0;
 
for (int i = 0; i< num; i++){
     read.getline(d[i].name,30);
     read >>d[i].money;
     read.getline(str,1);
     if(d[i].money>10000){
         bigger++;
     }
}
 
if (bigger > 0&& bigger < num){
     cout <<"Grand Patrons" << endl;
     for (int i =0; i < num; i++){
         if(d[i].money>10000){
             cout<< d[i].name << "\t" << d[i].money << endl;
         }
     }
     cout <<"Patrons" << endl;
     for (int i =0; i < num; i++){
         if(d[i].money <= 10000){
             cout<< d[i].name << "\t" << d[i].money << endl;
         }
     }
     return 0;
}
 
if (bigger == 0){
     cout <<"Grand Patrons" << endl;
     cout <<"none" << endl;
     cout <<"Patrons" << endl;
     for (int i =0; i < num; i++){
         if(d[i].money <= 10000){
             cout<< d[i].name << "\t" << d[i].money << endl;
         }
     }
     return 0;
}
 
if (bigger ==num){
     cout <<"Grand Patrons" << endl;
     for (int i =0; i < num; i++){
         if(d[i].money>10000){
             cout<< d[i].name << "\t" << d[i].money << endl;
         }
     }
     cout <<"Patrons" << endl;
     cout <<"none" << endl;
}
 
delete[]d;
return 0;
}