HPlogo HP C/HP-UX Reference Manual: Version A.05.55.02 > Chapter 2 Program Organization

Structuring a C Program

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When you write a C program, you can put all of your source code into one file or spread it across many files. A typical C source file contains some or all of the following components:

  • Preprocessor directives

  • Variables

  • Functions

Example 2-1 Example

The following shows how a program can be organized:

/* preprocessor directives */
#include <stdio.h>
#define WEIGHTING_FACTOR 0.6

/* global typedef declaration */
typedef float THIRTY_TWO_BIT_REAL;

/* global variable declaration */
THIRTY_TWO_BIT_REAL correction_factor = 1.15;

/* prototype */
float average (float arg1, THIRTY_TWO_BIT_REAL arg2);

/* start of function body */
{

/* local variable declaration */
   float mean;

/* assignment statement */
   mean = (arg1 * WEIGHTING_FACTOR) + (arg2 * (1.0 - WEIGHTING_FACTOR));

/* return statement */
return (mean * correction_factor);

/* end of function body */

}

int main(void)

   /* start of function body */
{
   
   /* local variable declarations */
   float value1, value2, result;

   /* statements */
   printf("Enter two values -- ");
   scanf("%f%f", &value1, &value2);
   result = average(value1, value2);

   /* continuation line */
   printf("The weighted average using a correction \
   factor of %4.2f is %5.2f\n", correction_factor, result);

   /* end of function body */
}
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