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



class C_expr
{
public:
	C_expr	();
	C_expr	( unsigned int deg, char c );
	// ~C_expr	();

	inline int  GetCoef	( unsigned int deg ) const;
	char* OutputStr	( char *str );

	C_expr operator+( char *str );
	template<class T>C_expr operator^( const T& a )	// for test
	{ return *this; }
	C_expr operator+=( char *str );

private:
	int *coef;
	unsigned int degree;
	char symbolX;

	inline void GetMemory	( unsigned int deg );
	void InitZero	();
	inline void CopyData( C_expr *Dest );
	void CopyCoefs( C_expr *Dest );
	inline void SetCoef	( int num, unsigned int deg ) const;
	int DistanceToNextMark( char *str);
	void DeleteChars( char *str, char c);
	int GetDegreeFromStr( char *str);
};

C_expr::C_expr()
{
	degree = 2;
	symbolX = 'x';
	GetMemory( degree );
	InitZero();
}

C_expr::C_expr( unsigned int deg, char c )
{
	degree = deg;
	symbolX = c;
	GetMemory( degree );
	InitZero();
}

// C_expr::~C_expr(){ free( coef ); }

void C_expr::DeleteChars( char *str, char c )
{
	unsigned int i;
	const unsigned int len = strlen(str);

	for( i = 0; str[i] != '\0'; i++ )
	{
		if( str[i] == c )
			strcpy_s( str+i, len, str+i+1 );
	}
}

int C_expr::DistanceToNextMark( char *str )	// ret: find: distance, not find: -1
{
	const unsigned int i = strcspn( str, "+-" );

	return ( i < strlen(str) )? i: -1 ;
}

inline void C_expr::GetMemory( unsigned int deg )
{
	coef = (int*)malloc( sizeof(int)* (deg+1) );
}

void C_expr::InitZero()
{
	unsigned int i;

	for( i = 0; i <= degree; i++ )
		coef[i] = 0;
}

char* C_expr::OutputStr( char *str )
{
	int i;
	char tmp[ 100]; // TO DO

	strcpy_s( str, degree,  "" );

	for( i = degree; i >= 0 ; i-- )
	{
		if( i == 0 )	sprintf_s( tmp, 100, "%d",coef[i] );
		else			sprintf_s( tmp, 100, "%dx^%d + ",coef[i] ,i );

		strcat_s( str, 100, tmp );
	}

	return str;
}

inline void C_expr::CopyData( C_expr *Dest )
{
	Dest->symbolX = symbolX;	// mp
	CopyCoefs( Dest );			// p
}

void C_expr::CopyCoefs( C_expr *Dest )
{
	unsigned int i;
	for( i = 0; i <= degree; i++ )
		Dest->coef[i] = coef[i];
}

inline void C_expr::SetCoef( int num, unsigned int deg ) const
{
	coef[deg] = num;
}

inline int C_expr::GetCoef( unsigned int deg ) const
{
	return coef[deg];
}

int C_expr::GetDegreeFromStr( char *str )
{
	char *p;
	const int distance2nextmark = DistanceToNextMark(str);
	
	p = strchr( str, '^');
	
	if( p != NULL && ( p < str+distance2nextmark || distance2nextmark == -1 ) )
		return atoi(p+1);
	else
		return 0;

}

C_expr C_expr::operator+( char *str )
{
	// --  -- //
	int num;
	unsigned int deg;
	const unsigned int len = strlen(str);
	char *copystr; 
	bool Flag_continue;
	int distance2nextmark;

	C_expr expr_tmp(degree, symbolX);


	// --  -- //
	CopyData( &expr_tmp );

	copystr = new char( len+1 );		// obt@m
	strcpy_s( copystr, len+1, str );	// Rs[

	DeleteChars( copystr, ' ' );
	DeleteChars( copystr, '*' );


	// -- (O) -- //
	do
	{
		// --  -- //
		num = (copystr[0] == symbolX)? 1: atoi( &copystr[0] ) ;	// W( 1,atoi )
		deg = GetDegreeFromStr( copystr );					// 

		// --  -- //
		expr_tmp.SetCoef( expr_tmp.GetCoef(deg) + num, deg );


		// --  -- //
		distance2nextmark = DistanceToNextMark(copystr);
		Flag_continue = ( distance2nextmark == -1)? false: true ;

		// --  -- //
		if( Flag_continue )
		{
			strcpy_s( copystr, len, copystr+distance2nextmark+1 );	// Ll.
		}

	}while( Flag_continue );

	return expr_tmp;
}

C_expr C_expr::operator+=( char *str )
{
	// --  -- //
	int num;
	unsigned int deg;
	const unsigned int len = strlen(str);
	char *copystr; 
	bool Flag_continue;
	int distance2nextmark;


	// --  -- //
	copystr = new char( len+1 );		// obt@m
	strcpy_s( copystr, len+1, str );	// Rs[

	DeleteChars( copystr, ' ' );
	DeleteChars( copystr, '*' );

	// -- (O) -- //
	do
	{
		// --  -- //
		num = (copystr[0] == 'x')? 1: atoi( &copystr[0] ) ;	// W( 1,atoi )
		deg = GetDegreeFromStr( copystr );					// 

		// --  -- //
		SetCoef( GetCoef(deg) + num, deg );


		// --  -- //
		distance2nextmark = DistanceToNextMark(copystr);
		Flag_continue = ( distance2nextmark == -1)? false: true ;

		// --  -- //
		if( Flag_continue )
		{
			strcpy_s( copystr, len, copystr+distance2nextmark+1 );	// Ll.
		}

	}while( Flag_continue );

	return *this;
}



//C_expr::template<class T>C_expr operator^( const T& a );



int main(void)
{
	char str[100];

	C_expr expr(2,'x');

	// --  0 0 0 -- //
	printf( "before : %s\n", expr.OutputStr(str) );

	// --  -- //
	expr += "2*x^2+ 3x^1 + 3 +6x^2";
	expr^x;
	// -- X --//
	printf( "after  : %s\n", expr.OutputStr(str) );

	return 0;
}