I am just starting to learn about pointers using the C programming language and I am crossed up on this particular code example they have in the book I'm using:
#include <stdio.h>
#define SIZE 10
void bubbleSort( int * const array, const size_t size ); // prototype
int main( void )
{
// initialize array a
int a[ SIZE ] = { 2, 6, 4, 8, 10, 12, 89, 68, 45, 37 };
size_t i; // counter
puts( "Data items in original order" );
// loop through array a
for ( i = 0; i < SIZE; ++i )
{
printf( "%4d", a[ i ] );
} // end for
bubbleSort( a, SIZE ); // sort the array
puts( "\nData items in ascending order" );
// loop through array a
for ( i = 0; i < SIZE; ++i )
{
printf( "%4d", a[ i ] );
} // end for
puts("");
return 0;
}
// sort an array of integers using bubble sort algorithm
void bubbleSort( int * const array, const size_t size )
{
void swap( int *element1Ptr, int *element2Ptr ); // prototype
unsigned int pass; // pass counter
size_t j; // comparison counter
// loop to control passes
for ( pass = 0; pass < size - 1; ++pass )
{
// loop to control comparisons during each pass
for ( j = 0; j < size - 1; ++j )
{
// swap adjacent elements if they’re out of order
if ( array[ j ] > array[ j + 1 ] )
{
swap( &array[ j ], &array[ j + 1 ] );
} // end if
} // end inner for
} // end outer for
} // end function bubbleSort
// swap values at memory locations to which element1Ptr and
// element2Ptr point
void swap( int *element1Ptr, int *element2Ptr )
{
int hold = *element1Ptr;
*element1Ptr = *element2Ptr;
*element2Ptr = hold;
} // end function swap
What I am not understanding is why is this not giving any errors, since I see that in the parameters for the bubbleSort function, there is a const in front of array, making the array it's pointing to a const so that it cannot be changed. But in this function, we are swapping the elements from the array so shouldn't that produce an error due to the fact that changes to the array are made? I'm assuming that it maybe I'm not understanding precisely how pointers work in this context?
