第三章作业第一部分-优快云博客

本文链接：https://blog.youkuaiyun.com/u014029112/article/details/22108259

本文详细介绍了C++编程的基础知识，并通过多个实例代码展示了如何实现简单的编程任务，包括变量声明、运算符使用、控制结构、函数定义及调用等核心概念。此外，还涉及了基本的数据类型、字符串操作、条件判断与循环结构的应用。

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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;
}

例3.2

# 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;
}

例3.3

# 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;
}

例3.4

# 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;
}

例3.5

# 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;
}

例3.6

# 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;
}

习题3

# 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;
}

习题4

# 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;
}

习题5

# 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;
}

习题6

# 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;
}

习题7

# 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;
}

习题9

# 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;
}

习题10

# 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;
}

习题11

# 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;
}