C++例题练习(2)

环境：Dev-C++( Version:5.6.1)

1.循环输入一个1-1000的整数，判断是否为素数(输入1时程序结束)

　　素数：只能被1和自身整除.

　　实现代码：

#include <iostream>
#include <cstdlib>
#include <cassert>
using namespace std;
/*
 *function name:isPrimeNumber.
 *precondition:parameter value is more than zero and less than or equal one thousand.
 *postcondition:return true when parameter value is prime number.
*/
bool isPrimeNumber(const int &number);

int main()
{
    while(true)
    {
        int number;
        cout<<"please input a integer number(0-1000):"<<endl;
        cin>>number;
        //condition
        assert(number>&&number<=);
        if(number == ) {
            break;
        }

        bool flag;
        flag = isPrimeNumber(number);
        if(flag) {
            cout<<"yes, the number is prime number."<<endl;
        } else {
            cout<<"no, the number is not prime number."<<endl;
        }
    }
    return EXIT_SUCCESS;
}
bool isPrimeNumber(const int &number)
{
    for(int i=;i<number/+;i++) {
        if(number%i == ) {
            return false;
        }
    }
    return true;
} 

2.用类来实现输入和输出时间（时：分：秒）

要求：将数据成员改为私有；将输入和输出的功能有成员函数实现；在类体内定义成员函数

代码实现：

（对于时间输入的合理性，简单的采用断言assert函数来进行处理，不合理，程序直接结束运行）

 #include <iostream>
 #include <cstdlib>
 #include <cassert>
 using namespace std;
 class Time
 {
     public:
         void set_time()
         {
             cout<<"hour(0-23):"<<endl;
             cin>>hour;
             assert(hour>&&hour<);

             cout<<"minute(0-59):"<<endl;
             cin>>minute;
             assert(minute>&&minute<);

             cout<<"second(0-59):"<<endl;
             cin>>sec;
             assert(sec>&&sec<);
         }
         void show_time()
         {
             cout<<"time:"<<endl;
             cout<<hour<<":"<<minute<<":"<<sec<<endl;
         }
     private:
         int hour;
         int minute;
         int sec;
 };
 int main()
 {
     Time t;
     t.set_time();
     t.show_time();
     return EXIT_SUCCESS;
 }

3.在上题的基础上进行修改：在类体内声明成员函数，而在类外定义成员函数

　　代码实现：

 #include <iostream>
 #include <cstdlib>
 #include <cassert>
 using namespace std;
 class Time
 {
     public:
         void set_time();
         void show_time();
     private:
         int hour;
         int minute;
         int sec;
 };
 void Time::set_time()
 {
     cout<<"hour(0-23):"<<endl;
     cin>>hour;
     assert(hour>&&hour<);

     cout<<"minute(0-59):"<<endl;
     cin>>minute;
     assert(minute>&&minute<);

     cout<<"second(0-59):"<<endl;
     cin>>sec;
     assert(sec>&&sec<);
 }
 void Time::show_time()
 {
       cout<<"time:"<<endl;
     cout<<hour<<":"<<minute<<":"<<sec<<endl;
 }
 int main()
 {
     Time t;
     t.set_time();
     t.show_time();
     return EXIT_SUCCESS;
 }

4.求三个长方柱的体积

　　由成员函数完成如下功能：

1>由键盘分别输入3个长方柱的长，宽，高；

　　　　   2>计算长方柱的体积；

3>输出3个长方柱的体积；

　　实现代码:

 #include <iostream>
 #include <cstdlib>
 #include <cassert>
 using namespace std;
 class Box
 {
      public:
          void set_box();
          void volume()
          {
              cout<<"volume :"<<length*width*height<<endl;
          }
     private:
          double length;
          double width;
          double height;
 };
 /*
  *precondition:null
  *postcondition:set instance data
 */
 void Box::set_box()
 {
     cout<<"please enter the length, width and height of a rectangle:"<<endl;
     cin>>length>>width>>height;
     assert(length>&&width>&&height>);
 }
 int main()
 {
     Box box1;
     box1.set_box();
     box1.volume();

     Box box2;
     box2.set_box();
     box2.volume();

     Box box3;
     box3.set_box();
     box3.volume();
     return EXIT_SUCCESS;
 }