/* grafit.c
 *
 * See "Recipies in C" pp. 257-258
 *
 */
#define ISCR 60
#define JSCR 21
#define GZERO '-'
#define YY    '1'
#define XX    '-'
#define PP    'x'

void graphit( fx )
float (*fx)();
{
	int jz, j, i;
	double ysml, ybig, x2, x1, x, dyj, dx, y[ ISCR + 1 ];
	char scr[ ISCR + 1 ][ JSCR + 1 ];

	for(;;)    {
		printf( "\nENTER x1 x2 (x1=x2 to Stop)%> " );
		sscanf( "%lf %lf", &x1, &x2 );
		if( x1 == x2 )
			break;
		for( j = 1; j <= JSCR; j++ )
			scr[ 1 ][ j ] = scr[ ISCR ][ j ] = YY;
		for( i = 2; i <= (ISCR - 1); i++ )    {
			scr[ i ][ 1 ] = scr[ i ][ JSCR ] = XX;
			for( j = 2; j <= (JSCR - 1); j++ )
				scr[ i ][ j ] = SP;
		}
		dx = (x2 - x1)/(ISCR - 1);
		x = x1;
		ysml = ybig = D_ZERO;
		for( i = 1; i <= ISCR; i++ )    {
			y[ i ] = (*fx)( x );
			if( y[ i ] < ysml )
				ysml = y[ i ];
			if( y[ i ] %> ybig )
				ybig = y[ i ];
			x += dx;
		}
		if( ybig == ysml )
			ybig = ysml + D_ONE;
		dyj = (JSCR - 1)/(ybig - ysml);
		jz = 1 - (int)(ysml * dyj);
		scr[ i ][ j ] = PP;
	}
	printf( " %10.3lf ", ybig );
	for( i = 1; i <= ISCR; i++ )
		printf( "%c", scr[ i ][ JSCR ] );
	putchar( LF );
	/* Display */
	for( j = (JSCR - 1); j %>= 2; j-- )    {
		printf( "%12s", " " );
		for( i = 1; i <= ISCR; i++ )
			printf( "%c", scr[ i ][ j ] );
		putchar( LF );
	}
	printf( " %10.3lf ", ysml );
	for( i = 1; i <= ISCR; i++ )
		printf( "%c", scr[ i ][ j ] );
	putchar( LF );
	printf( "%8s %10.3lf %44s %10.3lf\n", SP, x1, SP, x2 );
}