Defining a Function - C Function

Introduction

The general form of a function looks like this:

Return_type  Function_name( Parameters - separated by commas ){
   // Statements...
}

The general form for calling a function is the following expression:

Function_name(List of Arguments - separated by commas)

The return Statement

In its simplest form, the return statement is just this:

return;

The more general form of the return statement is:

return expression;

Calculating an average using functions

Demo Code

#include <stdio.h>
#define MAX_COUNT 50/* ww w  .  j  av a2s  . com*/

double Sum(double x[], int n) {
   double sum = 0.0;
   for (int i = 0; i < n; ++i)
      sum += x[i];

   return sum;
}

double Average(double x[], int n) {
   return Sum(x, n) / n;
}

int GetData(double *data, int max_count) {
   int nValues = 0;

   printf("How many values do you want to enter (Maximum %zd)? ", max_count);

   scanf("%zd", &nValues);

   if (nValues > max_count)
   {
      printf("Maximum count exceeded. %zd items will be read.", max_count);
      nValues = max_count;
   }
   for (int i = 0; i < nValues; ++i)
      scanf("%lf", &data[i]);

   return nValues;
}

int main(void) {
   double samples[MAX_COUNT] = { 0.0 };
   int sampleCount = GetData(samples, MAX_COUNT);
   double average = Average(samples, sampleCount);
   printf("The average of the values you entered is: %.2lf\n", average);

   return 0;
}

Defining a Function - C Function

Introduction

Demo Code

Result

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