第四周作业（1）

#include <iostream>
using namespace std;
int main()
{
double i=1.0,e=1.0;
int n=1;
for(;i>=1E-6;n++)
{
i=i/n;
e+=i;
}
cout<<"e="<<e<<endl;
return 0;

}

#include <iostream>
#include <cmath>
using namespace std;
int main()
{
int i;
double pi=0,f=1;
for(i=1;i<10e6;i+=2)
{
pi+=4*(double)1/i*f;
f*=-1;
}
cout << "pi约等于："<<pi<<endl;
return 0;
}

#include <iostream>
using namespace std;
int main()
{
int n;
cout << "请输入一个数："<<endl;
cin >> n ;
if(n<10)
cout<<n<<" <10"<<endl;
else if(n<100)
cout<<n<<" 10 ~ 100."<<endl;
else if (n<1000)
cout<<n<<" 100 ~ 1000."<<endl;
else cout << n<<" > 1000"<<endl;
return 0;
}

#include<iostream>
#include<iomanip>
using namespace std;

int main()
{
cout<<setiosflags(ios::internal)<<endl;
cout<<setw(7)<<"*"<<endl;
cout<<setw(9)<<"* * *"<<endl;
cout<<setw(11)<<"* * * * *"<<endl;
cout<<setw(12)<<"* * * * * *"<<endl;
cout<<setw(11)<<"* * * * *"<<endl;
cout<<setw(9)<<"* * *"<<endl;
cout<<setw(7)<<"*"<<endl;

return 0;

}

#include<iostream>
using namespace std;

void main()
{
double a,b,count;
b=0;
for(a=1;b<=1000;a++)
{
b+=a*a;
count=a;
}

cout<<count<<endl;
}

#include<iostream>
#include<iomanip>
using namespace std;

int main()
{
int a;
double b,money_1,money_2;
money_1=0;
b=0.01;
money_2=0;
for(a=1;a<=30;a++)
{
money_1+=10e4;
b*=2;
money_2+=b;

}

cout<<"富人给了陌生人"<<fixed<<money_2<<"元"<<endl;
cout<<"陌生人给了富人"<<fixed<<money_1<<"元"<<endl;
return 0;

}

#include <iostream>
using namespace std;
int main()
{
int i=1;
int t=1;
while(i<=9)
{

while(t<=i)
{
cout<<t<<"*"<<i<<"="<<i*t<<" ";
t++;
}
t=1;
cout<<endl;
i++;
}
return 0;
}

#include<iostream>
using namespace std;
int main()
{
int i=0;
int x,y,z;
double money;
for(x=0;x<=20;x++)
{
for(y=0;y<34;y++)
{
z=100-x-y;
money=5*x+3*y+z/3.0;

if(money==100)
{
i++;
cout<<endl;
cout<<"第"<<i<<"种情况"<<endl;
cout<<"鸡翁的数量x="<<x<<endl;
cout<<"鸡母的数量y="<<y<<endl;
cout<<"鸡雏的数量z="<<z<<endl;

}
}
}
return 0;
}

#include<iostream>
using namespace std;

int main()
{
int a,b,sum,i,j,count;
cout<<"输入一个整数"<<endl;
cin>>a;
b=a;
count=0;
sum=0;
for(i=1;a>0;i++)

{
a=a/10;
count++;
}
cout<<"它总共是由"<<count<<"位数组成"<<endl;
for(j=0;j<count;j++)
{
sum+=b%10;
b=b/10;
}
cout<<"各个数位上数字之和为"<<sum<<endl;
return 0;
}

#include<iostream>
#include<cmath>
using namespace std;
int main()
{
float x,y,tmp;
cout<<"\t请输入x，y的坐标:\n\n";
cin>>x;
cin>>y;
cout<<"  你输入坐标为： <"<<x<<','<<y<<">\n\n";
x=fabs(x);
y=fabs(y);
tmp=sqrt((x-2)*(x-2)+(y-2)*(y-2));//原理是算出输入的点距塔所在的点的距离。
if(tmp<=1 && tmp>=0)                  //判断是否在塔的半径(r = 1)内;
cout<<"  该点建筑物的高度是 10m \n\n";
else
cout<<"  该点建筑物的高度是 0m \n\n";
return 0;
}

#include<iostream>
using namespace std;
int main()
{
double  num,i,j=1,temp=0;
cout<<"请输入一个正整数计算其阶乘\n\n";
cin>>num;
for(i=1;i<=num;i++)
{
j*=i;
temp+=j;
}
cout<<num<<"!="<<j<<'\n';
cout<<"累加之和为："<<temp<<"\n";
return 0;
}

#include<iostream>
using namespace std;
int main()
{
int x=1,i=9,j;
for(i;i>=1;i--)
x=(x+1)*2;
cout<<"这贪吃的猴子一共吃了"<<x<<"个苹果\n";
return 0;
}