C++第二章习题

布满荆棘的人生 2023-07-09 02:17 15阅读 0赞

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1.

#include <iostream>
    
    int main()
    { 
        using namespace std;
        char first[20], last[20];
        cout << "Enter your first name:\n";
        cin >> first;
        cout << "Enter your last name:" << endl;
        cin >> last;
        cout << "Hi, " << first << ' ' << last << endl;
        return 0;
    }

Enter your first name:
    Man
    Enter your last name:
    Wu
    Hi, Man Wu

#include <iostream>
    int main()
    { 
        using namespace std;
        cout << "Enter a distance in long.\n";
        float distance;
        cin >> distance;
        cout << distance << " long equals to " << distance * 220 << " yard.\n";
        return 0;
    }

可以看到float只有6位有效位（和小数点没关系！）

Enter a distance in long.
    2.111144141
    2.11114 long equals to 464.452 yard.

#include <iostream>
    void mice();
    void run();
    
    int main()
    { 
        mice();
        mice();
        run();
        return 0;
    }
    
    void mice()
    { 
        std::cout << "Three blind mice\n";
    }
    
    void run()
    { 
        std::cout << "See how they run\nSee how they run\n";
    }

记住函数原型，然后这次main不需要using指令，子函数里我觉得只用cout不需要名称空间

Three blind mice
    Three blind mice
    See how they run
    See how they run

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

Enter your age:
    23
    Your age contains 276 months.

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#include <iostream>
    float tempTransform(float celsius);
    int main()
    { 
        std::cout << "Enter a temperature in Celsius:\n";
        float celsius, fahrenheit;
        std::cin >> celsius;
        fahrenheit = tempTransform(celsius);
        std::cout << celsius << " degrees Celsius is " << fahrenheit << " degrees Fahrenheit.\n";
        return 0;
    }
    
    float tempTransform(float celsius)
    { 
        float f;
        f = 9 * celsius / 5 + 32;
        return f;
    }

即使是float，也没有默认加小数点哦

Enter a temperature in Celsius:
    20
    20 degrees Celsius is 68 degrees Fahrenheit.

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#include <iostream>
    double LightToAstro(double light);
    int main()
    { 
        using namespace std;
        cout << "Enter the number of light years:\n";
        double light, astro;
        cin >> light;
        astro = LightToAstro(light);
        cout << light << " light years = " << astro << " astronomical units.\n";
    
        return 0;
    }
    
    double LightToAstro(double light)
    { 
        return light * 63240;
    }

Enter the number of light years:
    4.2
    4.2 light years = 265608 astronomical units.

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#include <iostream>
    void showTime(int hours, int minutes);
    int main()
    { 
        std::cout << "Enter the number of hours:\n";
        int hours, minutes;
        std::cin >> hours;
        std::cout << "Enter the number of minutes:\n";
        std::cin >> minutes;
        showTime(hours, minutes);
        return 0;
    }
    
    void showTime(int hours, int minutes)
    { 
        std::cout << "Time: " << hours << ":" << minutes << std::endl;//注意endl也要有前缀啊
    }

Enter the number of hours:
    9
    Enter the number of minutes:
    28
    Time: 9:28

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