第三章作业

作业一

习题5

#include<iostream>
usingnamespacestd;
intmain()
{
doublei=1.0,e=1.0;
intn=1;
for(;i>=1E-6;n++)
{
i=i/n;
e+=i;
}
cout<<"e="<<e<<endl;
return0;

}

习题6
#include<iostream>

usingnamespacestd;

intmain()
{

doublei=1,pai=0.0;
intn=1;

for(;i>=1E-6;n++)
{

i=1/(double)(2*n-1);//关键注意要强制转换double

if(n%2==0)

pai=pai-i;
else

pai=pai+i;
}

cout<<"pai="<<4*pai<<endl;
return0;

}

习题8
#include<iostream>
#include<iomanip>

usingnamespacestd;

intmain()
{

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;

return0;

}

习题9

#include<iostream>
usingnamespacestd;

voidmain()

{
doublea,b,count;

b=0;
for(a=1;b<=1000;a++)

{
b+=a*a;
count=a;
}

cout<<count<<endl;

}

习题10
#include<iostream>
#include<iomanip>

usingnamespacestd;

intmain()
{

inta;
doubleb,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<<"富人给了穷人"<<fixed<<money_2<<"元"<<endl;

cout<<"穷人给了富人"<<fixed<<money_1<<"元"<<endl;
return0;

}

习题11
#include<iostream>
usingnamespacestd;

intmain()

{
inta,b,product;

for(a=1;a<=9;a++)
{

for(b=1;b<=9;b++)
{

product=a*b;
cout<<b<<"*"<<a<<"="<<product<<"\t";

}

cout<<endl;

}
return0;

}

作业二

#include<iostream>
usingnamespacestd;

intmain()
{
introoster,hen,chick,n=0;
for(rooster=1;rooster<=20;rooster++)
for(hen=1;hen<=33;hen++)
{
chick=100-hen-rooster;
if((chick%3==0)&&(5*rooster+3*hen+chick/3==100))
cout<<"方法"<<++n<<"rooster="<<rooster<<"hen="<<hen<<"chick="<<chick<<endl;
}

return0;
}

作业三

#include<iostream>
usingnamespacestd;

intmain()
{
inta,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;

return0;
}

作业四

//任意坐标点到各个圆心点的半径小于等于一时说明该点在建筑物的范围内#include<iostream>
#include<cmath>usingnamespacestd;
intmain()
{floatx,y,juli;
cout<<"输入任何一个坐标横轴和纵轴的值"<<endl;cin>>x;
cout<<"x="<<x<<endl;cin>>y;
cout<<"y="<<y<<endl;/*各个象限的点到各个圆柱的距离都等于该点所对应的第一象限的点到第一象限圆柱的距离*/
x=fabs(x),y=fabs(y);juli=sqrt((x-2)*(x-2)+(y-2)*(y-2));
if(juli<=1)cout<<"该点建筑物高度为10米"<<endl;
elsecout<<"该点建筑物高度为0米"<<endl;
return0;
}

作业五
#include<iostream>
usingnamespacestd;

intmain()
{
longi,p,n,sum;
cout<<"请输入一个整数"<<endl;
cin>>n;
sum=0;
p=1;
for(i=1;i<=n;i++)
{
p*=1;
sum+=p;
}
cout<<"1！+2！+3！+.....+n！="<<sum<<endl;
return0;

}