/* You'll need this file for an assignment. Read it and run it and become
   familiar with it so that I can refer to it in class. Bring it along to class.
   from "C Programming: A Modern Approach, Study Guide". */




/* --------- ch9/plot.c :-------------------------*/
#include <stdio.h>
#include <math.h>

#define MAX_COLUMNS 60

float xl, xu, delta, ymin, ymax;

void print_header();
void get_domain_parameters();
void calculate_min_max();
void print_plot_header();
void print_plot_footer();
void print_plot();
main()
 {
print_header();
get_domain_parameters();
calculate_min_max();
print_plot();
return 0;
 }

void print_header()
 {
printf("\n==============================================\n");
printf(" Sine Function Plotting Program\n");
printf("==============================================\n");
printf("\n");
 }

void get_domain_parameters()
 {
printf("Please enter lower bound for domain: ");
scanf("%f", &xl);
 printf("Please enter upper bound for domain: ");
 scanf("%f", &xu);
 printf("Please enter interval over domain: ");
 scanf("%f", &delta);

 printf("\nYou entered the following domain parameters:\n");
 printf(" ===========================================\n");
 printf(" Lower bound for domain: %f\n", xl);
 printf(" Upper bound for domain: %f\n", xu);
 printf(" Increment value : %f\n", delta);
 printf(" ===========================================\n\n");
 }

 void calculate_min_max()
 {
 float x, y;

 ymin = sin(xl);
 ymax = sin(xl);
 for (x = xl; x <= xu; x += delta) {
 y = sin(x);
 if (y < ymin) ymin = y;
 if (y > ymax) ymax = y;
 }
 }

 void print_plot_header()
 {
 printf(" %3.1f", ymin);
 printf(" %3.1f", (ymin + ymax) / 2);
 printf(" %3.1f\n", ymax);
 printf(" +");
 printf("-----------------------------+");
 printf("------------------------------+\n");
 }

 void print_plot_footer()
 {
 printf(" +");
 printf("-----------------------------+");
 printf("------------------------------+\n");
 printf(" %3.1f", ymin);
 printf(" %3.1f", (ymin + ymax) / 2);
 printf(" %3.1f\n", ymax);
 }

 void print_plot()
 {
 int scale_index, i, previous;
 float x;
 char A[MAX_COLUMNS];

 for (i = 0; i < MAX_COLUMNS; i++)
 A[i] = ' ';
 x = xl;
 previous = 0;
 print_plot_header();

 /*************************************************************/
 /* Loop through values of x in the domain, in incs of delta */
 /*************************************************************/
 while (x <= xu) {

 /***********************************************************/
 /* Calculate scale_index: number of spaces to the left of */
 /* the asterisk. Keep track of previous location of the */
 /* asterisk. In each iteration, place a space in the */
 /* previous location, and an asterisk in the current one. */
 /***********************************************************/
 scale_index = (sin(x) - ymin) * MAX_COLUMNS / (ymax - ymin) - 0.5;
 A[previous] = ' ';
 A[scale_index] = '*';
 previous = scale_index;
 printf("%5.2f |", x);
 for (i = 0; i < MAX_COLUMNS; i++)
 putchar(A[i]);
 printf("|\n");
 x = x + delta;
 }
 print_plot_footer();
 }