基本数据类型.txt

钱能主编 C++程序设计教程（第一版） 该书习题的答案代码

cout<<"\x07operating \tsystem\n";     //实现响铃且显示

//cout的一种用法，提高可读性
cout<<"My Name is Jone \n"
    <<"the ID is "
    <<2
    <<endl;

//*************************
//**      ch2_1.cpp      **
//*************************

#include <iostream.h>
#include <iomanip.h>

void main()
{
	double amount = 22.0/7;
	cout<<amount<<endl;
	cout<<setprecision(0)<<endl
	    <<setprecision(1)<<endl
	    <<setprecision(2)<<endl
	    <<setprecision(3)<<endl
	    <<setprecision(4)<<endl;

	cout<<setiosflags(ios::fixed);
	cout<<setprecision(8)<<amount<<endl;

	cout<<setiosflags(ios::scientific)<<amount<<endl;

	cout<<setprecision(6);
}

//设置值的输出宽度 setw()
cout<<setw(8)            //cmp the two display results
    <<10
    <<20
    <<endl;

cout<<setw(8)<<10
    <<setw(8)<<20
    <<endl;

//*************************
//**      ch2_2.cpp      **
//*************************

#include <iostream.h>

void main()
{
	int number =1001;
	cout<<"Decimal:"<<dec<<number<<endl
	    <<"Hexadecimal:"<<hex<<number<<endl
	    <<"Octal:"<<oct<<number<<endl;
}

//**************************
//**      ch2_2e.cpp      **
//**************************

#include <iostream.h>
#include <iomanip.h>

void main()
{
	int number =1001;
	cout<<"Hexadecimal:"<<hex
	    <<setiosflags(ios::uppercase)
	    <<number<<endl;
}

//*************************
//**      ch2_3.cpp      **
//*************************

#include <iostream.h>
#include <iomanip.h>

void main()
{
	cout<<setfill('*')
	cout<<setw(2)<<21<<endl
	cout<<setw(3)<<21<<endl
	cout<<setw(4)<<21<<endl;
	cout<<setfill('');
}

//*************************
//**      ch2_4.cpp      **
//*************************

#include <iostream.h>
#include <iomanip.h>

void main()
{
	cout<<setiosflags(ios::right)
	    <<setw(5)<<1
	    <<setw(5)<<2
	    <<setw(5)<<3<<endl;
	cout<<setiosflags(ios::left)
	    <<setw(5)<<1
	    <<setw(5)<<2
	    <<setw(5)<<3<<endl;
}

//*************************
//**      ch2_5.cpp      **
//*************************

#include <iostream.h>
#include <iomanip.h>

void main()
{
	cout<<10.0/5<<endl;
	cout<<setiosflags(ios::showpoint)
	    <<10.0/5<<endl;
}


//*************************
//**      ch2_6.cpp      **
//*************************

#include <iostream.h>
#include <iomanip.h>

void main()
{
	cout<<10<<" "<<-20<<endl;

	cout<<setiosflags(ios::showpos)
	    <<10<<" "<<-20<<endl;
}