题： 编写一个程序，如下输出实例所示的请求并显示信息：
What is your first name? Betty Sue
Waht is your last name? Yewe
What letter grade do you deserve? B
What is your age? 22
Name: Yewe, Betty Sue
Grade: C
Age: 22
程序应接受的名字包含多个单词。另外，程序将向下调整成绩。假设用户请求A、B或C，返回 B、C 或 D。
解：
#include <iostream>
int main() {
using namespace std;
char first_name[40];
char last_name[40];
char grade_letter;
int age;
cout << "What is your first name: ";
cin.getline(first_name, 40);
cout << "What is your last name: ";
cin.getline(last_name, 40);
cout << "What letter grade do you deserve: ";
cin >> grade_letter;
cout << "What is your age: ";
cin >> age;
cout << "Name: " << last_name << ", " << first_name << endl;
cout << "Grade: " << char(grade_letter+1) << "\n";
cout << "Age: " << age << endl;
return 0;
}
题： 修改程序清单4.4，使用 C++ string 类而不是 char 数组。
解：
#include <iostream>
#include <string>
int main() {
using namespace std;
string name;
string dessert;
cout << "Enter your name: \n";
getline(cin, name);
cout << "Enter your favorite dessert:\n";
getline(cin, dessert);
cout << "I have delicious " << dessert;
cout << " for you, " << name << ".\n";
return 0;
}
题： 编写一个程序，它要求用户首先输入其名，然后输入其姓；然后程序使用一个逗号和空格将姓和名组合起来，并存储和显示组合结果。请使用char数组和头文件cstring中的函数。下面是该程序运行时的 情形：
Enter your first name: Flip
Enter your last name: Fleming
Here's the information in a single string: Fleming, Flip
解：
#include <iostream>
#include <cstring>
int main() {
using namespace std;
char first_name[20], last_name[20];
char final_name[50];
cout << "Enter your first name: ";
cin.getline(first_name, 20);
cout << "Enther your last name: ";
cin.getline(last_name, 20);
strcpy(final_name, last_name);
strcat(final_name, ", ");
strcat(final_name, first_name);
cout << "Here's the information in a single string: " << final_name << endl;
return 0;
}
题： 编写一个程序，它要求用户首先输入其名，再输入其姓；然后程序使用一个逗号和空格将姓和名组合起来，并存储和显示组合结果。请使用string对象和头文件string中的函数。下面是该程序运行时的情形：
Enter your first name: Flip
Enter your last name: Fleming
Here's the information in a single string: Fleming, Flip
解：
#include <iostream>
#include <string>
int main() {
using namespace std;
string first_name, last_name;
string final_name;
cout << "Enter your first name: ";
getline(cin, first_name);
cout << "Enther your last name: ";
getline(cin, last_name);
final_name = last_name + ", " + first_name;
cout << "Here's the information in a single string: " << final_name << endl;
return 0;
}
题： 结构体 CandyBar 包含3个成员。第一个成员存储了糖块的品牌；第二个成员存储糖块的重量（可以有小数）；第三个成员存储了糖块的卡路里含量（整数）。编写一个程序，声明这个结构体，创建一个名为 snack 的 CandyBar 变量，并将其成员分别初始化为 "Mocha Munch"、2.3 和 350。初始化应在声明 snack 时进行。最后，程序显示 snack 变量的内容。
解：
#include <iostream>
#include <string>
struct CandyBar
{
std::string name;
double weight;
int calories;
};
int main() {
using namespace std;
CandyBar snack = {"Mocha Munch", 2.3, 350}; // 初始化结构体
cout << "The name of the CandyBar: " << snack.name << "\n";
cout << "The weight of the candy: " << snack.weight << "\n";
cout << "The calories information: " << snack.calories << endl;
return 0;
}
题： 结构体 CandyBar 包含3个成员，如 编程练习5所示。请编写一个程序，创建一个包含 3 个元素的 CandyBar 数组，并将它们初始化为所选择的值，然后显示每个结构体的内容。
解：
#include <iostream>
#include <string>
struct CandyBar
{
std::string name;
double weight;
int calories;
};
int main() {
using namespace std;
CandyBar candbar[3] = {
{"Mocha Munch", 2.3, 350},
{"Big Rabbit", 5, 300},
{"Joy Boy", 4.1, 430}
};
cout << "The name of the CandyBar: " << candbar[0].name << "\n"
<< "The weight of the candy: " << candbar[0].weight << "\n"
<< "The calories information: " << candbar[0].calories << "\n\n";
cout << "The name of the CandyBar: " << candbar[1].name << "\n"
<< "The weight of the candy: " << candbar[1].weight << "\n"
<< "The calories information: " << candbar[1].calories << "\n\n";
cout << "The name of the CandyBar: " << candbar[2].name << "\n"
<< "The weight of the candy: " << candbar[2].weight << "\n"
<< "The calories information: " << candbar[2].calories << endl;
return 0;
}
题： William Wingate从事比萨饼分析服务。对于每个披萨饼，他都需要记录下列信息：
- 披萨饼公司的名称，可以有多个单词组成；
- 披萨饼的直径；
- 披萨饼的重量。
请设计一个能够存储这些信息的结构体，并编写一个使用这种结构体变量的程序。程序将请求用户输入上述信息，然后显示这些信息。请使用 cin（或其它的方法）和cout。
解：
#include <iostream>
#include <string>
struct Pizza
{
std::string company;
double diameter;
double weight;
};
int main() {
using namespace std;
Pizza pizza;
cout << "Enter the pizza company: ";
getline(cin, pizza.company);
cout << "Enter the diameter of pizza: ";
cin >> pizza.diameter;
cout << "Enter the weight of pizza: ";
cin >> pizza.weight;
cout << "\nHere is the pizza information: \n"
<< "Company: " << pizza.company << "\n"
<< "Diameter: " << pizza.diameter << "\n"
<< "Weight: " << pizza.weight << endl;
return 0;
}
题： 完成编程练习7，但使用 new 来为结构体分配内存，而不是声明一个结构体变量。另外，让程序在请求输入比萨饼公司名称之前输入比萨饼的直径。
解：
#include <iostream>
#include <string>
struct Pizza
{
std::string company;
double diameter;
double weight;
};
int main() {
using namespace std;
Pizza *pizza = new Pizza;
cout << "Enter the diameter of pizza: ";
cin >> pizza->diameter;
cout << "Enter the weight of pizza: ";
cin >> pizza->weight;
// 注意上语句输入完 weight 后，回车键留在输入流中，以下的 getline
// 碰到输入流中的回车就以为结束了，所以如果没有这个 cin.get() 先读
// 取回车，那么用户永远获得 company 的值。
cin.get();
cout << "Enter the pizza company: ";
getline(cin, pizza->company);
cout << "\nHere is the pizza information: \n"
<< "Company: " << pizza->company << "\n"
<< "Diameter: " << pizza->diameter << "\n"
<< "Weight: " << pizza->weight << endl;
delete pizza;
return 0;
}
题： 完成编程练习6，但使用 new 来动态分配数组，而不是声明一个包含 3 个元素的 CandyBar 数组。
解：
#include <iostream>
#include <string>
struct CandyBar
{
std::string name;
double weight;
int calories;
};
int main() {
using namespace std;
CandyBar *p_candybar = new CandyBar [3] {
{"Mocha Munch", 2.3, 350},
{"Big Rabbit", 5, 300},
{"Joy Boy", 4.1, 430}
};
// 输出第一个结构体元素，按照数组的方式输出
cout << "The name of the CandyBar: " << p_candybar[0].name << "\n"
<< "The weight of the candy: " << p_candybar[0].weight << "\n"
<< "The calories information: " << p_candybar[0].calories << "\n\n";
// 输出第二个结构体元素，可以按照指针的逻辑输出
cout << "The name of the CandyBar: " << (p_candybar+1)->name << "\n"
<< "The weight of the candy: " << (p_candybar+1)->weight << "\n"
<< "The calories information: " << (p_candybar+1)->calories << "\n\n";
// 输出第三个结构体元素，又是数据的方式
cout << "The name of the CandyBar: " << p_candybar[2].name << "\n"
<< "The weight of the candy: " << p_candybar[2].weight << "\n"
<< "The calories information: " << p_candybar[2].calories << endl;
delete [] p_candybar;
return 0;
}
题： 编写一个程序，让用户输入三次 40 码跑的成绩（如果您愿意，也可让用户输入40米跑的成绩），并显示次数和平均成绩。请使用一个 array对象来存储数据（如果编译器不支持 array 类，请使用数组）。
解：
#include <iostream>
#include <array>
int main() {
using namespace std;
array<double, 3> result;
cout << "Enter threed result of the 40 meters runing time: \n";
cin >> result[0];
cin >> result[1];
cin >> result[2];
double ave_result = (result[0] + result[1] + result[2]) / 3;
cout << "The all three time results are: " << result[0] << ", "
<< result[1] << ", " << result[2] << endl;
cout << "The average result: " << ave_result << endl;
return 0;
}