Passing arrays and individual array elements to functions : Array Parameter « Array « C Tutorial

1. C Tutorial
2. Array
3. Array Parameter

#include <stdio.h>
#define SIZE 5

void modifyArray( int b[], int size ); 
void modifyElement( int e );

int main()
{
   int a[ SIZE ] = { 0, 1, 2, 3, 4 }; 
   int i; 

   printf( "Effects of passing entire array by reference:\n\nThe "
          "values of the original array are:\n" );

   for ( i = 0; i < SIZE; i++ ) { 
      printf( "%3d", a[ i ] );
   } 

   printf( "\n" );

   modifyArray( a, SIZE );  

   printf( "The values of the modified array are:\n" );

   for ( i = 0; i < SIZE; i++ ) {
      printf( "%3d", a[ i ] );
   } 

   printf( "\n\n\nEffects of passing array element "
           "by value:\n\nThe value of a[3] is %d\n", a[ 3 ] );
   
   modifyElement( a[ 3 ] ); 

   printf( "The value of a[ 3 ] is %d\n", a[ 3 ] );
   
   return 0; 

}

void modifyArray( int b[], int size )
{
   int j; 

   for ( j = 0; j < size; j++ ) {
      b[ j ] *= 2;
   } 

}

void modifyElement( int e )
{
   printf( "Value in modifyElement is %d\n", e *= 2 );
}

Effects of passing entire array by reference:

The values of the original array are:
  0  1  2  3  4
The values of the modified array are:
  0  2  4  6  8


Effects of passing array element by value:

The value of a[3] is 6
Value in modifyElement is 12
The value of a[ 3 ] is 6