C++作业四—分数的累加，星形图案,百钱白鸡问题

#include <iostream>
using namespace std;
int main()
{
double i,k(1),sum(0);
for(i=1;i<=20;i=i+2)
{
sum=sum+(k*i)/(i+2);
k=-k;
}
cout<<"sum="<<sum<<endl;
return 0;
}

#include <iostream>
using namespace std;
int main ()
{
int i,j;
for (i=1;i<=6;i++)
if (i<6)
{for (j=1;j<=11;j++)
if (j==5+i||j==7-i)
cout<<"*";
else cout<<" ";
cout<<endl;
}
else
cout<<"***********"<<endl;
return 0;
}

#include <iostream>
using namespace std;
int main()
{
int x,y,n=1;
double z;
for( x=0;x<=20;x++)
for( y=0;y<=33;y++)
for( z=0;z<100;z++)
if (5*x+3*y+z/3==100&&x+y+z==100)
cout<<n++<<"鸡翁"<<x<<"只"<<"鸡母"<<y<<"只"<<"鸡雏"<<z<<"只"<<endl;
return 0;
}