c++primer 第二章编程练习答案

2.7.1

#include<iostream>
int main() {
    using namespace std;
    char name[20];
    char address[20];
    cout << "input name :";
    cin >> name;
    cout << "input address:";
    cin >> address;
    cin.get();
    cout << "name is " << name;
    cout << endl;
    cout << "address is " << address;
    cin.get();
}

2.7.2

#include<iostream>
int main() {
    using namespace std;
    int distance;
    cout << "input distance:";
    cin >> distance;
    cin.get();
    cout << "long_distance is ";
    cout << distance * 220;
    cin.get();
}

2.7.3

#include<iostream>
using namespace std;
void func_1();
void func_2();
int main() {
    //cin.get();
    func_1();
    func_1();
    func_2();
    func_2();
    cin.get();
}
void func_1() {
    cout << "Three blind mice" << endl;
}
void func_2() {
    cout << "See how they run" << endl;
}

2.7.4

#include<iostream>
int main() {
    using namespace std;
    int age;
    cout << "Enter your age:";
    cin >> age;
    cin.get();
    cout << age * 12;
    cin.get();
}

2.7.5

#include<iostream>
double convert(double);
int main() {
    using namespace std;
    double degrees;
    cout << "Please enter a Celsius value: ";
    cin >> degrees;
    cin.get();
    cout << degrees << " Celsius is " << convert(degrees) << " degrees Fahrenheit";
    cin.get();
}
double convert(double degrees) {
    double Fahrenheit = degrees*1.8 + 32.0;
    return Fahrenheit;
}

2.7.6

#include<iostream>
double convert(double);
int main() {
    using namespace std;
    double light_years;
    cout << "Enter the number of light years: ";
    cin >> light_years;
    cin.get();
    cout << light_years << " light years = " << convert(light_years) << " astronomical units";
    cin.get();
}
double convert(double light_years) {
    double units = light_years * 63240;
    return units;
}

2.7.7

#include<iostream>
void timer(int, int);
int main() {
    using namespace std;
    int hours, minutes;
    cout << "Enter the number of hours: ";
    cin >> hours;
    cout << "Enter the number of minutes: ";
    cin >> minutes;
    cin.get();
    timer(hours, minutes);
    cin.get();
}
void timer(int hours, int minutes) {
    std::cout << "Timer: " << hours << ":" << minutes;
}