C++ Primer Plus（第6版）第3章处理数据-优快云博客

复习题

1
一种整型不能满足编程的需求
2
short shit=80;
unsigned shit=42110;
auto shit=3000000000;
3
没提供措施，自己小心
4
33L是long类型，33是int类型
5
等价
6
(1) int shit=88;std::cout<<(char)shit;
(2) char shit=88;std::cout<<shit;
7
如果浮点型中用于存储小数的位数>=整型的位数，就不会有舍入误差。否则，就会有。
查limits.h和float.h，自己解决。
8
74 4 0 4.5 3
9
(1) int shit=(int)x1+(int)x2;
(2) int shit=x1+x2;
10
int float char char32_t double

编程练习

3.1

#include<iostream>
int main(void)
{
    using namespace std;
    cout<<"输入你的身高，以英寸为单位\n";
    int inch;
    cin>>inch;
    cout<<"你身高"<<inch/12<<"英尺"<<inch%12<<"英寸\n";
    return 0;
}

3.2

#include<iostream>
int main(void)
{
    using namespace std;
    const int inch_per_foot=12;
    const double meter_per_inch=0.0254;
    const double pound_per_kg=2.2;
    cout<<"输入你的身高，以英尺和英寸的方式\n你身高的英尺数：";
    int foot;
    cin>>foot;
    cout<<"你身高的英寸数：";
    int inch;
    cin>>inch;
    cout<<"输入你的体重，以磅为单位\n你的体重是：";
    int pound;
    cin>>pound;
    inch=foot*12+inch;
    double meter=inch*meter_per_inch;
    double kg=pound/pound_per_kg;
    double BMI=kg/meter/meter;
    cout<<"你的身高 "<<meter<<"米\n你的体重 "<<kg<<"公斤\n你的BMI "<<BMI<<endl;
    return 0;
}

3.3

#include<iostream>
int main(void)
{
    using namespace std;
    const int minutes_per_degrees=60;
    const int seconds_per_minutes=60;
    cout<<"Enter a latitude in degrees,minutes,and seconds:\n";
    cout<<"First enter the degrees:";
    int degrees;
    cin>>degrees;
    cout<<"Next,enter the minutes of arc:";
    int minutes;
    cin>>minutes;
    cout<<"Finally,enter the seconds of arc:";
    int seconds;
    cin>>seconds;
    cout<<degrees<<" degrees, "<<minutes<<" minutes, "<<seconds<<" seconds = "
            <<degrees+(double)minutes/minutes_per_degrees+(double)seconds/minutes_per_degrees/seconds_per_minutes
            <<"degrees";
    return 0;
}

3.4

#include<iostream>
int main(void)
{
    using namespace std;
    const int hpd=24;
    const int mph=60;
    const int spm=60;
    const int spd=hpd*mph*spm;
    const int sph=mph*spm;
    cout<<"Enter the number of seconds:";
    long seconds;
    cin>>seconds;
    cout<<seconds<<" seconds = "<<seconds/spd<<" days, "<<seconds%spd/sph<<" hours, "
            <<seconds%spd%sph/spm<<" minutes, "<<seconds%spd%sph%spm<<" seconds\n";
    return 0;
}

3.5

#include<iostream>
int main(void)
{
    using namespace std;
    cout<<"Enter the world's population:";
    long long world;
    cin>>world;
    cout<<"Enter the population of the US:";
    long long US;
    cin>>US;
    cout<<"The population of the US is "<<(double)US/world*100<<"% of the world population.\n";
    return 0;
}

3.6

#include<iostream>
int main(void)
{
    using namespace std;
    const double mpk=0.6214;
    const double lpg=3.785;
    cout<<"输入驱车里程(英里) ";
    double mile;
    cin>>mile;
    cout<<"输入耗油量(加仑) ";
    double gallon;
    cin>>gallon;
    cout<<"汽车耗油量为"<<mile/gallon<<"英里每加仑\n";
    double km=mile/mpk;
    double liter=gallon*lpg;
    cout<<"每百公里耗油量为"<<liter/km*100<<"升\n";
    return 0;
}

3.7

#include<iostream>
int main(void)
{
    using namespace std;
    const double mpk=0.6214;
    const double lpg=3.785;
    cout<<"输入每百公里耗油量(升) ";
    double liter;
    cin>>liter;
    double gallon;
    gallon=liter/lpg;
    double mile;
    mile=mpk*100;
    cout<<"每百公里耗油量为"<<liter<<"升\n";
    cout<<"汽车耗油量为"<<mile/gallon<<"英里每加仑\n";
    return 0;
}