C++ primer第一章习题

#include <iostream>

 

using std::cout;

using std::endl;

using std::cin;

 

int main()

{

  //1.3

  cout<<"Hello,Word!"<<endl;

 

  //1.4

  int num1,num2;

  cin>>num1>>num2;

  cout<<"num1 乘以num2 的结果为："<<num1 * num2<<endl;

 

  //1.9

  int sum=0;

  for(int i=-100;i<=100;++i)

  {

       sum+=i;

  }

  cout<<sum;//结果为

 

  //1.10(1)

  int sumF(0);

 for(int i=50;i<=100;++i)

 {

      sumF+=i;

 }

 cout<<sumF<<endl;

  //1.10(2)

 int sumW(0);

 int j=100;

 while(j>=50)

 {

      sumW+=j;

      j--;

 }

 cout<<sumW<<endl;

 

     //1.11(1)

     int i=10;

     while(i>=0)

     {

         cout<<i<<endl;

         i--;

     }

     //1.11(2)

      for(int j=10;j>=0;--j)

      {

          cout<<j;

      }

    

 

     //1.16

     int a(0),b(0);

     cin>>a>>b;

     if(a>b)

     {

         cout<<a;

     }

     else

     {

         cout<<b;

     }

 

     //1.17

     int num(0);

     int result(0);

     while(cin>>num)

     {

      if(num<0)

       {

           result++;

       }

     }

     cout<<result<<endl;

 

     //1.18+1.19

     int num1(0),num2(0);

     int count(0);

     cin>>num1>>num2;

     if(num1==num2)

     {

         cout<<"不能相等！";

         return 0;

     }

     else if(num1>num2)

     {

         for(num1;num1>=num2;num1--)

         {

              cout<<num1<<"   ";

              count++;

              if(count%10==0)

              {

                   cout<<endl;

              }

         }

         return 0;

     }

     else {

         while(num1<=num2)

         {

         cout<<num1<<"   ";

          num1++;

          count++;

          if(count%10==0)

              {

                   cout<<endl;

              }

         }

         return 0;                  

     }

  system("pause");

}