#include <stdio.h>
void graphit(int, int, double*, double, double, double);
double	rhi, rlow, rrange;


main()
	{
	int m = 6;
	double dat[] = {15.0,25.0,35.0,45.0,55.0,65.0};
	graphit(1,m,dat,25.0, 40.0, 55.0);
	graphit(2,m,dat,25.0, 40.0, 55.0);
	graphit(3,m,dat,25.0, 40.0, 55.0);
	}

static inline int graphmark(double value) { return (int) 1+15*2*(value-rlow)/rrange; }

void graphit(int ctype, int m, double *x, double lcl, double cl, double ucl)
/*
 *  ctype = chart type: 1=xbar, 2=R, 3=p
 *  m = number of statistical values
 *  x[] = vector of m statistics, with first value in x[0]
 *  lcl = lower control limit
 *  cl  = center line
 *  ucl = upper control limit
 */
	{
	register int i,j;
	int ilcl, icl, iucl;
	double	res;
	static char *fhd     = "%4s %9s[i]%12s  %s\n";
	static char buf[]     =  "                                 ";
	static char heading[] =  "---------------------------------";
	static char type[][20] = { "x-bar", "R", "p"};
	char isave;

	// normalize data first and calculate heading strings here
	
	printf("\n\t\t\t*** %s CONTROL CHART  ***\n",&type[ctype-1][0]);
	printf("\nLCL = %lf   CL = %lf   UCL = %lf\n\n",lcl,cl,ucl);

	for (i=0,rhi=ucl,rlow=lcl; i < m; ++i) 
			{
			if (x[i] > rhi) rhi = x[i];
			if (x[i] < rlow) rlow = x[i];
			}
	rrange = rhi-rlow;
	ilcl = graphmark(lcl);
	icl  = graphmark(cl);
	iucl = graphmark(ucl);

	heading[icl] 	= 'C';
	heading[ilcl]	= 'L';
	heading[iucl]	= 'U';
	buf[icl] = buf[ilcl] = buf[iucl] = '|';

	printf(fhd,"i.",&type[ctype-1][0],"   ",heading);
	for (i=0; i<m; ++i)
		{
		printf("%3d. %12.2lf%12s", i+1,x[i]," ");
		j		= graphmark(x[i]);
		isave   = buf[j];
		buf[j]	= ((x[i]>=lcl)&&(x[i]<=ucl))? '*' : '#';
		printf("  %s\n",buf);
		buf[j]	= isave;
		}
	printf(fhd,"",&type[ctype-1][0],"",heading);
	buf[icl] = buf[ilcl] = buf[iucl] = ' ';
	}