float_c.c

用C++实现的利用整型数实现浮点运算的系列方法重载.

#include<stdlib.h>
#include<stdio.h>
#include<iostream.h>

class CFloat
{
private:
	long  m_Data;
	int   m_Dec;
public:
	CFloat( long data, int dec );
	CFloat( void );
	~CFloat();

    void  setData( long data, int dec );
    void  show( void );
	CFloat &operator +( CFloat &data );
	CFloat &operator -( CFloat &data );
	CFloat &operator *( CFloat &data );
	CFloat &operator /( CFloat &data );
	CFloat &operator =( CFloat &data );
	
};

CFloat::CFloat( long data, int dec )
{
	setData( data, dec );
}

CFloat::CFloat( void )
{
    m_Data = 0;
    m_Dec = 0;
}

CFloat::~CFloat( void )
{
}

void CFloat::setData( long data, int dec )
{
    m_Data = data;
    m_Dec = dec;
}
void CFloat::show( void )
{
    cout << " data = " << m_Data << ", dec = " << m_Dec << endl;
}

CFloat &CFloat::operator+ ( CFloat &data )
{
	long  first_int, first_dec, second_int, second_dec;
	int   first_modulus, second_modulus, i;

	first_modulus = 1;
	second_modulus = 1;
	for( i = 0; i < m_Dec; i++ )
	{
		first_modulus *= 10;
	}
	for( i = 0; i < data.m_Dec; i++ )
	{
		second_modulus *= 10;
	}
	first_int = m_Data / first_modulus;
	second_int = data.m_Data / second_modulus;
	first_dec = m_Data % first_modulus;
	second_dec = data.m_Data % second_modulus;
	if( m_Dec < data.m_Dec )
	{
	    for( i = m_Dec; i < data.m_Dec; i++ )
	    {
	        first_dec *= 10;
	    }
	}
	else if( m_Dec > data.m_Dec )
	{
	    for( i = data.m_Dec; i < m_Dec; i++ )
	    {
	        second_dec *= 10;
	    }
	}
	first_int += second_int;
	first_dec += second_dec;

    if( m_Dec < data.m_Dec )
    {
        first_modulus = second_modulus;
    }

	first_int = first_int + first_dec / first_modulus;

	first_dec %=  first_modulus;
	m_Data = first_int * first_modulus + first_dec;
	m_Dec  = m_Dec > data.m_Dec ? m_Dec : data.m_Dec;

	return *this;	
}

CFloat &CFloat::operator -( CFloat &data )
{
	long  first_int, first_dec, second_int, second_dec;
	int   first_modulus, second_modulus, i;

	first_modulus = 1;
	second_modulus = 1;
	for( i = 0; i < m_Dec; i++ )
	{
		first_modulus *= 10;
	}
	for( i = 0; i < data.m_Dec; i++ )
	{
		second_modulus *= 10;
	}
	first_int = m_Data / first_modulus;
	second_int = data.m_Data / second_modulus;
	first_dec = m_Data % first_modulus;
	second_dec = data.m_Data % second_modulus;
	if( m_Dec < data.m_Dec )
	{
	    for( i = m_Dec; i < data.m_Dec; i++ )
	    {
	        first_dec *= 10;
	    }
	}
	else if( m_Dec > data.m_Dec )
	{
	    for( i = data.m_Dec; i < m_Dec; i++ )
	    {
	        second_dec *= 10;
	    }
	}
	first_int -= second_int;
	first_dec -= second_dec;

    if( m_Dec < data.m_Dec )
    {
        first_modulus = second_modulus;
    }

	first_int = first_int + first_dec / first_modulus;

	first_dec %=  first_modulus;
	m_Data = first_int * first_modulus + first_dec;
	m_Dec  = m_Dec > data.m_Dec ? m_Dec : data.m_Dec;

	return *this;	
}

CFloat &CFloat::operator *( CFloat &data )
{
printf(" m_Data = %d, data.m_Data = %d, m_Dec = %d, data.m_Dec = %d\n", m_Data, data.m_Data, m_Dec, data.m_Dec );
	m_Data *= data.m_Data;
	m_Dec  = m_Dec + data.m_Dec;

	return *this;	
}

CFloat &CFloat::operator /( CFloat &data )
{
	long rslt, dec;
	int  i, symbol;
printf(" m_Data = %d, data.m_Data = %d, m_Dec = %d, data.m_Dec = %d\n", m_Data, data.m_Data, m_Dec, data.m_Dec );
    if( data.m_Data == 0 )
    {
        m_Data = 0;
        m_Dec = data.m_Dec;
        
        return *this;
    }
    symbol = 0;
    if(( m_Data > 0 && data.m_Data > 0 ) || (  m_Data < 0 && data.m_Data < 0 ))
    {
        symbol = 0;
    }
    else
    {
        if( m_Data < 0 )
        {
            m_Data = -m_Data;
        }
        if( data.m_Data < 0 )
        {
            data.m_Data = -data.m_Data;
        }
        symbol = 1;
    }
	i = 0;
	rslt = 0;
	dec = m_Data;
	while( i < 10 )
	{
		rslt = rslt * 10 + dec / data.m_Data;
		dec = dec % data.m_Data;
		if( dec == 0 )
		{
			break;
		}
		dec *= 10;
		i++;
	}
    if( symbol )
    {
        rslt = -rslt;
    }
	m_Data = rslt;
	m_Dec = i;

	return *this;
}

CFloat &CFloat::operator =( CFloat &data )
{
	m_Data = data.m_Data;
	m_Dec = data.m_Dec;

	return *this;
}

main( )
{
    long i, j, s, d;
    CFloat a, b;
    float f1, f2;
    
    srand( 10 );
    for( i = 0; i < 10; i++ )
    {
        s = rand() / 100000;
        d = s % 4;
        if( s % 2 == 1 )
        {
            s = -s;
        }
        f1 = ( float )s;
        for( j = 0; j < d; j++ )
        {
            f1 /= 10.0;
        }
        a.setData( s, d );
        s = rand() / 100000;
        d = s % 4;
        if( s % 2 == 1 )
        {
            s = -s;
        }
        f2 = ( float )s;
        for( j = 0; j < d; j++ )
        {
            f2 /= 10.0;
        }
        b.setData( s, d );
        a = a / b;
printf( " i = %d -- %f / %f = %f\n", i, f1, f2, f1 / f2 );
a.show();
    }
}