CHAPTER 1 
=========

(hello.c)

#include <stdio.h>

int main(void)
{
   printf("Hello, world!\n");
   return 0;
}

Source -> preprocssing -> compiling -> linking -> executable
hello.c                   "gcc hello.c -o hello"     hello

=============================================================

(pacific_sea.[ch])

/* Measuring the Pacific Sea. */

#include "pacific_sea.h"

int main(void)
{
   int         pacific_sea = AREA;     /* in sq kilometers */
   double      acres, sq_miles, sq_feet, sq_inches;

   printf("\nThe Pacific Sea covers an area");
   printf(" of %d square kilometers.\n", pacific_sea);
   sq_miles = SQ_MILES_PER_SQ_KILOMETER * pacific_sea;
   sq_feet = SQ_FEET_PER_SQ_MILE * sq_miles;
   sq_inches = SQ_INCHES_PER_SQ_FOOT * sq_feet;
   acres = ACRES_PER_SQ_MILE * sq_miles;
   printf("In other units of measure this is:\n\n");
   printf("%22.7e acres\n", acres);
   printf("%22.7e square miles\n", sq_miles);
   printf("%22.7e square feet\n", sq_feet);
   printf("%22.7e square inches\n\n", sq_inches);
   return 0;
}

=====

the file pacific_sea.h:
-----------------------

#include <stdio.h>

#define   AREA                        2337
#define   SQ_MILES_PER_SQ_KILOMETER   0.3861021585424458
#define   SQ_FEET_PER_SQ_MILE         (5280 * 5280)
#define   SQ_INCHES_PER_SQ_FOOT       144
#define   ACRES_PER_SQ_MILE           640

=====

output:
-------


The Pacific Sea covers an area of 2337 square kilometers.
In other units of measure this is:

         5.7748528e+05 acres
         9.0232074e+02 square miles
         2.5155259e+10 square feet
         3.6223572e+12 square inches


=============================================================

(getchar.c)

#include <stdio.h>

int main(void)
{
   int   c;

   while ((c = getchar()) != EOF)
      putchar(c);
   return 0;
}

=============================================================

(for_min_max.c)

/* Compute the minimum, maximum, sum, and average. */
#include <stdio.h>
#include <stdlib.h>
int main(void)
{
   int      i;
   double   x, min, max, sum, avg;

   if (scanf("%lf", &x) != 1) {
      printf("No data found - bye!\n");
      exit(1);
   }
   min = max = sum = avg = x;
   printf("%5s%9s%9s%9s%12s%12s\n%5s%9s%9s%9s%12s%12s\n\n",
      "Count", "Item", "Min", "Max", "Sum", "Average",
      "-----", "----", "---", "---", "---", "-------");
   printf("%5d%9.1f%9.1f%9.1f%12.3f%12.3f\n",
      1, x, min, max, sum, avg);
   for (i = 2; scanf("%lf", &x) == 1; ++i) {
      if (x < min)
         min = x;
      else if (x > max)
         max = x;
      sum += x;
      avg = sum / i;
      printf("%5d%9.1f%9.1f%9.1f%12.3f%12.3f\n",
         i, x, min, max, sum, avg);
   }
}

=============================================================

(for_minmax_func.c)

#include <stdio.h>

float   maximum(float x, float y);
float   minimum(float x, float y);
void    prn_info(void);

int main(void)
{
   int     i, n;
   float   max, min, x;

   prn_info();
   printf("Input n:  ");
   scanf("%d", &n);
   printf("\nInput %d real numbers:  ", n);
   scanf("%f", &x);
   max = min = x;
   for (i = 2; i <= n; ++i) {
      scanf("%f", &x);
      max = maximum(max, x);
      min = minimum(min, x);
   }
   printf("\n%s%11.3f\n%s%11.3f\n\n",
      "Maximum value:", max,
      "Minimum value:", min);
   return 0;
}

float maximum(float x, float y)
{
   if (x > y)
      return x;
   else
      return y;
}

float minimum(float x, float y)
{
   if (x < y)
      return x;
   else
      return y;
}

void prn_info(void)
{
   printf("\n%s\n%s\n\n",
      "This program reads an integer value for n, and then",
      "processes n real numbers to find max and min values.");
}


=============================================================

(bubble_sort.c)

#include <stdio.h>

#define   CLASS_SIZE   5

int main(void)
{
   int   i, j, score[CLASS_SIZE], sum = 0, tmp;

   printf("Input %d scores:  ", CLASS_SIZE);
   for (i = 0; i < CLASS_SIZE; ++i) {
      scanf("%d", &score[i]);
      sum += score[i];
   }
   for (i = 0; i < CLASS_SIZE - 1; ++i)       /* bubble sort */
      for (j = CLASS_SIZE - 1; j > i; --j)
         if (score[j-1] < score[j]) {     /* check the order */
            tmp = score[j-1];
            score[j-1] = score[j];
            score[j] = tmp;
         }
   printf("\nOrdered scores:\n\n");
   for (i = 0; i < CLASS_SIZE; ++i)
      printf("   score[%d] =%5d\n", i, score[i]);
   printf("\n%18d%s\n%18.1f%s\n\n",
      sum, " is the sum of all the scores",
      (double) sum / CLASS_SIZE, " is the class average");
   return 0;
}


output:
-------

Input 5 scores:  63  88  97  53  77

Ordered scores:

   score[0] =   97
   score[1] =   88
   score[2] =   77
   score[3] =   63
   score[4] =   53

               378 is the sum of all the scores
              75.6 is the class average

=============================================================

(nice_day.c)

/* Have a nice day! */

#include <ctype.h>
#include <stdio.h>

#define   MAXSTRING   100

int main(void)
{
   char   c, name[MAXSTRING];
   int    i, sum = 0;

   printf("\nHi!  What is your name?  ");
   for (i = 0; (c = getchar()) != '\n'; ++i) {
      name[i] = c;
      if (isalpha(c))
	 sum += c;
   }
   name[i] = '\0';
   printf("\n%s%s%s\n%s",
      "Nice to meet you ", name, ".",
      "Your name spelled backwards is ");
   for (--i; i >= 0; --i)
      putchar(name[i]);
   printf("\n%s%d%s\n\n%s\n",
      "and the letters in your name sum to ", sum, ".",
      "Have a nice day!");
   return 0;
}