hist.c

linux下的Ｃ语言开发

/********************************************************
 * 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>     
#include <memory.h>
/*
 * Define the number of lines int the histogram
 */
#define NUMBER_OF_LINES 30	/* Number of lines in the histogram */
const int DATA_MIN = 1;		/* Number of the smallest item */
const int DATA_MAX = 30;	/* Number of the largest item */
/*
 * WARNING: The number of items from DATA_MIN to DATA_MAX (inclusive)
 * must match the number of lines.
 */

/* number of characters wide to make the histogram */
const int WIDTH = 60;

static struct infinite_array data_array;
static int data_items;

int main(int argc, char *argv[])
{
    /* Function to read data */
    void read_data(const char name[]);

    /* Function to print the histogram */
    void  print_histogram(void);

    if (argc != 2) {
        fprintf(stderr, "Error:Wrong number of arguments\n");
        fprintf(stderr, "Usage is:\n");
        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(const char name[])
{
    char  line[100];    /* line from input file */
    FILE *in_file;      /* input file */
    int data;           /* data from input */

    in_file = fopen(name, "r");
    if (in_file == NULL) {
        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, "%d", &data) != 1) {
            fprintf(stderr,
              "Error: Input data not integer number\n");
            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];    

    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 */

    memset(counters, '\0', sizeof(counters));

    for (index = 0; index < data_items; ++index) {
        int data;/* data for this point */

        data = ia_get(&data_array, index);

        if ((data < DATA_MIN) || (data > DATA_MAX))
            ++out_of_range;
        else {
            ++counters[data - DATA_MIN];
            if (counters[data - DATA_MIN] > max_count)
                max_count = counters[data - DATA_MIN];
        }
    }

    scale = ((float) max_count) / ((float) WIDTH);

    for (index = 0; index < NUMBER_OF_LINES; ++index) {
        /* index for outputting the dots */
        int   char_index;
        int   number_of_dots;   /* number of * to output */

        printf("%2d (%4d): ", index + DATA_MIN, counters[index]);

        number_of_dots = (int) (((float) counters[index]) / scale);
        for (char_index = 0; 
	     char_index < number_of_dots;
             ++char_index) {
            printf("*");
	}
        printf("\n");
    }
    printf("%d items out of range\n", out_of_range);
}