// Passing arrays and individual array elements to functions.
#include <stdio.h>
#define SIZE 5
// function prototypes
void modifyArray( int b[], size_t size );
void modifyElement( int e );
// function main begins program execution
int main( void )
{
int a[ SIZE ] = { 0, 1, 2, 3, 4 }; // initialize array a
size_t i; // counter
puts( "Effects of passing entire array by reference:\n\nThe "
"values of the original array are:" );
// output original array
for ( i = 0; i < SIZE; ++i ) {
printf( "%3d", a[ i ] );
} // end for
puts( "" );
// pass array a to modifyArray by reference
modifyArray( a, SIZE );
puts( "The values of the modified array are:" );
// output modified array
for ( i = 0; i < SIZE; ++i ) {
printf( "%3d", a[ i ] );
} // end for
// output value of a[ 3 ]
printf( "\n\n\nEffects of passing array element "
"by value:\n\nThe value of a[3] is %d\n", a[ 3 ] );
modifyElement( a[ 3 ] ); // pass array element a[ 3 ] by value
// output value of a[ 3 ]
printf( "The value of a[ 3 ] is %d\n", a[ 3 ] );
} // end main
// in function modifyArray, "b" points to the original array "a"
// in memory
void modifyArray( int b[], size_t size )
{
size_t j; // counter
// multiply each array element by 2
for ( j = 0; j < size; ++j ) {
b[ j ] *= 2; // actually modifies original array
} // end for
} // end function modifyArray
// in function modifyElement, "e" is a local copy of array element
// a[ 3 ] passed from main
void modifyElement( int e )
{
// multiply parameter by 2
printf( "Value in modifyElement is %d\n", e *= 2 );
} // end function modifyElement
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