第三章作业第一部分

例3.1

# include<iostream>
using namespace std;
int main()
{
cout<<"This is a program.\n";
cout<<"This"<<"is"<<"a"<<"program.\n";
cout<<"This"
<<"is"
<<"a"
<<"program.\n";
return 0;
}

# include<iostream>
using namespace std;
int main()
{
int a=10;
int b=20;
int c=30;
cout<<"a="<<a<<"\n"
<<"b="<<b<<"\n"
<<"c="<<c<<"\n"
<<"(a+c)/(2*b)="<<(a+c)/(2*b)<<"\n";
return 0;
}

# include<iostream>
using namespace std;
int main()
{
int n1,n2;
cout<<"Please input two numbers:";
cin>>n1>>n2;
cout<<"The average of the two numbers is"<<(n1+n2)/2.0<<"\n";
return 0;
}

# include<iostream>
using namespace std;
int main()
{
cout<<"河北建筑工程学院"<<endl;
cout<<"计算机系"<<endl;
return 0;
}

# include<iostream>
# include<iomanip>
using namespace std;
int main()
{
int x=30,y=300,z=1024;
cout<<"Decimal:"<<'\t'
<<"x="<<x<<"\t\t"
<<"y="<<y<<"\t\t"
<<"z="<<z<<endl;
cout<<"Octal:"<<"\t\t"<<oct
<<"x="<<x<<"\t\t"
<<"y="<<y<<"\t\t"
<<"z="<<z<<endl;
cout<<"Hexadecimal:"<<'\t'<<hex
<<"x="<<x<<"\t\t"
<<"y="<<y<<"\t\t"
<<"z="<<z<<endl;
cout<<setiosflags(ios::uppercase);
cout<<"Hexadecimal:"<<'\t'
<<"x="<<x<<"\t\t"
<<"y="<<y<<"\t\t"
<<"z="<<z<<endl;
cout<<resetiosflags(ios::uppercase);
cout<<"Hexadecimal:"<<'\t'
<<"x="<<x<<"\t\t"
<<"y="<<y<<"\t\t"
<<"z="<<z<<endl;
cout<<"Decimal:"<<'\t'<<dec
<<"x="<<x<<"\t\t"
<<"y="<<y<<"\t\t"
<<"z="<<z<<endl;
return 0;
}

# include<iostream>
# include<iomanip>
using namespace std;
int main()
{
int a=10;
int b=1000;
cout<<setw(5)<<a<<endl
<<setw(2)<<b<<endl;
return 0;
}

# include<iostream>
using namespace std;
int main()
{
int i,j;
for(i=0;i<5;i++)
{
for(j=i;i<5;j++)
cout<<"*";
cout<<endl;
}
return 0;
}

# include<iostream>
using namespace std;
int main()
{
int i,j,k,count=0;
for(i=1;j<=9;i++)
for(j=0;j<=9;j++)
if j==i continue;
else for(k=0;k<=9;k++)
if k!=i&&k!=j count++;
cout<<count<<endl;
return 0;
}

# include<iostream>
using namespace std;
int main()
{
long double e=1.0;
long double f=1;
for(int i=1;1.0/f>=1e-6;i++)
{
f*=i;
e+=1.0/f;
}
cout<<"自然对数e的近似值为:"<<e<<endl;
return 0;
}

# include<iostream>
using namespace std;
int main()
{
long double pi=1.0;
double flag=-1.0;
for(int i=3;1.0/i>=1e-6;i+=2)
{
pi+=flag/i;
flag= -flag;
}
cout<<"圆周率pi的近似值为:"<<4*pi<<endl;
return 0;
}

# include<iostream>
using namespace std;
int main()
{
int number;
cout<<"请输入一个整数:";
cin>>number;
if(number<10)
cout<<number<<"is less than 10.";
else if(number<=99)
cout<<number<<"is 10 to 99.";
else if(number<=999)
cout<<number<<"is 100 to 999.";
else
cout<<number<<"is more than 1000.";
cout<<endl;
return 0;
}

# include<iostream>
using namespace std;
int main()
{
int sum=0,n;
for(n=1;;n++)
{
sum+=n*n;
if(sum>=10000)
break;
}
sum-=n*n;
cout<<"满足\"1*1+2*2+3*3+...+n*n<=1000\"的最大n值为"<<n-1<<endl
<<"其和为:"<<sum<<endl;
return 0;
}

# include<iostream>
using namespace std;
int main()
{
double day=0.01,stranger=0.0,millionaire=10.0;
for(int i=1;i<=30;i++)
{
stranger+=day;
day*=2;
}
stranger/=10000.0;
millionaire*=30;
cout<<"这一个月中陌生人给了百万富翁"<<millionaire<<"万元"<<endl
<<"百万富翁给了陌生人"<<stranger<<"万元"<<endl;
return 0;
}

# include<iostream>
using namespace std;
int main()
{
int row,column;
for(row=1,column=1;row<=9;row++)
{
for(column=1;column<=row;column++)
cout<<column<<"*"<<row<<"="<<row*column<<"\t";
cout<<endl;
}
return 0;
}