1 files changed, 142 insertions, 0 deletions
diff --git a/reference/C/CONTRIB/OR_PRACTICAL_C/17_2.c b/reference/C/CONTRIB/OR_PRACTICAL_C/17_2.c
new file mode 100644
index 0000000..57fdeae
--- /dev/null
+++ b/reference/C/CONTRIB/OR_PRACTICAL_C/17_2.c
@@ -0,0 +1,142 @@
+/********************************************************
+ * hist -- generate a histogram of an array of numbers  *
+ *                                                      *
+ * Usage                                                *
+ *      hist <file>                                     *
+ *                                                      *
+ * Where                                                *
+ *      file is the name of the file to work on         *
+ ********************************************************/
+#include "ia.h"
+#include <stdio.h>
+#include <stdlib.h>     /* ANSI Standard only */
+#include <mem.h>
+/*
+ * the following definitions define the histogram
+ */
+#define NUMBER_OF_LINES 50
+#define LOW_BOUND 0.0
+#define HIGH_BOUND 99.0
+/*
+ * if we have NUMBER_OF_LINES data to 
+ * output then each item must use
+ * the following factor
+ */
+#define FACTOR \
+  ((HIGH_BOUND - LOW_BOUND) / ((float) (NUMBER_OF_LINES-1)))
+
+/* number of characters wide to make the histogram */
+#define WIDTH 60   
+
+static struct infinite_array data_array;
+static int data_items;
+
+main(int argc, char *argv[])
+{
+    void  read_data(char *);    /* get the data into the array */
+    void  print_histogram(void);/* print the data */
+
+    if (argc != 2) {
+        (void) fprintf(stderr, 
+               "Error:Wrong number of arguments\n");
+        (void) fprintf(stderr, 
+               "Usage is:\n");
+        (void) fprintf(stderr, 
+               "  hist <data-file>\n");
+        exit(8);
+    }
+    ia_init(&data_array);
+    data_items = 0;
+
+    read_data(argv[1]);
+    print_histogram();
+    return (0);
+}
+/********************************************************
+ * read_data -- read data from the input file into      *
+ *              the data_array.                         *
+ *                                                      *
+ * Parameters                                           *
+ *      name -- the name of the file to read            *
+ ********************************************************/
+void read_data(char *name)
+{
+    char  line[100];    /* line from input file */
+    FILE *in_file; /* input file */
+    float data;    /* data from input */
+
+    in_file = fopen(name, "r");
+    if (in_file == NULL) {
+        (void) fprintf(stderr, 
+               "Error:Unable to open %s\n", name);
+        exit(8);
+    }
+    while (1) {
+        if (fgets(line, sizeof(line), in_file) == NULL)
+            break;
+
+        if (sscanf(line, "%f", &data) != 1) {
+            (void) fprintf(stderr,
+              "Error: Input data not floating point number\n");
+            (void) fprintf(stderr, "Line:%s", line);
+        }
+        ia_store(&data_array, data_items, data);
+        data_items++;
+    }
+    fclose(in_file);
+}
+/********************************************************
+ * print_histogram -- print the histogram output.       *
+ ********************************************************/
+void  print_histogram(void)
+{
+    /* upper bound for printout */
+    int   counters[NUMBER_OF_LINES];    
+    float low;          /* lower bound for printout */
+    int   out_of_range = 0;/* number of items out of bounds */
+    int   max_count = 0;/* biggest counter */
+    float scale;        /* scale for outputting dots */
+    int   index;        /* index into the data */
+
+    (void) memset((char *) counters, '\0', sizeof(counters));
+
+    for (index = 0; index < data_items; index++) {
+        float data;/* data for this point */
+
+        data = ia_get(&data_array, index);
+
+        if ((data < LOW_BOUND) || (data > HIGH_BOUND))
+            out_of_range++;
+        else {
+            /* index into counters array */
+            int   count_index;
+
+            count_index = (data - LOW_BOUND) / FACTOR;
+
+            counters[count_index]++;
+            if (counters[count_index] > max_count)
+                max_count = counters[count_index];
+        }
+    }
+
+    scale = ((float) max_count) / ((float) WIDTH);
+
+    low = LOW_BOUND;
+    for (index = 0; index < NUMBER_OF_LINES; index++) {
+        /* index for outputting the dots */
+        int   char_index;
+        int   number_of_dots;   /* number of * to output */
+
+        (void) printf("%2d:%3.0f-%3.0f (%4d): ",
+                      index, low, low + FACTOR -1, 
+                      counters[index]);
+
+        number_of_dots = (int) (((float) counters[index]) / scale);
+        for (char_index = 0; char_index < number_of_dots;
+             char_index++)
+            (void) printf("*");
+        (void) printf("\n");
+        low += FACTOR;
+    }
+    (void) printf("%d items out of range\n", out_of_range);
+}