Question

Your job is to change the program so that it no longer uses indexes anywhere within the executable code but instead uses pointers into the array. Hint: This will be easy to think about if you change all indexes in the program to pointers. It might make sense if you also change their names. Thus: int start_index; would become: int *start_ptr; Make sure that your program will correctly sort any set of numbers. Pay particular attention to the boundary cases (start and end of the array).

SORT.CPP

#include#include#include/*
  Program sorts an array of integers using a selection sort.
  The general algorithm repeatedly finds the smallest number
  in the array and places it at the front of the list.
*/
using namespace std;

const int size = 20;

int find_small_index (int start_index, int numbers []);
void swap_values (int index1, int index2, int numbers []);
void print (int numbers []);

int main(int argc, char *argv[])
{
    // array of numbers
    int numbers [size] = {7, 9, 21, 16, 65, 8, 32, 1, 17, 41,
                       54, 128, 62, 44, 12, 1023, 89, 905, 32, -12};
    int start_index;  // current starting spot for search
    int small_index;  // index of the smallest number in the array

    start_index = 0;
    // continue finding the smallest value and placing it
    // at the front of the list
    while (start_index < size - 1)
    {
          small_index = find_small_index (start_index, numbers);
          swap_values (small_index, start_index, numbers);
          start_index++;
    }

    cout << "\n\nThe sorted array is:\n";
    print (numbers);

    cout << "\n\n";

    return 0;
}

// finds and returns the index of the smallest number remaining in
// the array
int find_small_index (int start_index, int numbers [])
{
    int small_index, // smallest index to be returned
        index;       // current index being viewed

    small_index = start_index;
    // look at each element
    for (index = start_index + 1; index < size; index++)
        // remember index of smaller value
        if (numbers [index] < numbers [small_index])
           small_index = index;
    return small_index;
}

// swap the values in the array at indexes index1 and index2
void swap_values (int index1, int index2, int numbers [])
{
     int swapper;

     swapper = numbers [index1];
     numbers [index1] = numbers [index2];
     numbers [index2] = swapper;
}

// prints the array in nice format, 10 numbers per line
void print (int numbers [])
{
     int on_line,  // number of values printed on the line
         index;    // index of current number being printed

     on_line = 0;
     // print each element in the array
     for (index = 0; index < size; index++)
     {
         cout << setw (5) << numbers [index];
         on_line++;
         // if 10 numbers have been printed on the line
         // go to next line
         if (on_line == 10)
         {
            cout << "\n";
            on_line = 0;
         }
     }
}

Answer 1

Program:

SELECTIONSORT.CPP
#include
#include
#include

/*
Program sorts an array of integers using a selection sort.
The general algorithm repeatedly finds the smallest number
in the array and places it at the front of the list.
*/
using namespace std;

const int size = 20;

int find_small_value (int *start_pointer, int numbers []);
void swap_values (int *const, int *const,int numbers[]);
void print (int numbers []);

int main(int argc, char *argv[])
{
// array of numbers
int numbers [size] = {7, 9, 21, 16, 65, 8, 32, 1, 17, 41,
54, 128, 62, 44, 12, 1023, 89, 905, 32, -12};
int *start_pointer; // current starting spot for search
int *small_pointer; // pointer of the smallest number in the array

*start_pointer = 0;
// continue finding the smallest value and placing it
// at the front of the list
while (*start_pointer < size - 1)
{
*small_pointer = find_small_value (*start_pointer, numbers);
swap_values (*small_pointer, *start_pointer, numbers);
*start_pointer++;
}

cout << "\n\nThe sorted array is:\n";
print (numbers);

cout << "\n\n";

return 0;
}

// finds and returns the index of the smallest number remaining in
// the array
int find_small_value (int *start_pointer, int numbers [])
{
int *small_pointer, // smallest index to be returned
index; // current index being viewed

*small_pointer = *start_pointer;
// look at each element
for (index = *start_pointer + 1; index < size; index++)
// remember index of smaller value
if (numbers [index] < numbers [*small_pointer])
*small_pointer = index;
return *small_pointer;
  
}

// swap the values in the array at indexes index1 and index2
void swap_values (int *const pointer_value1, int *const pointer_value2, int numbers [])
{
int swapper;

swapper = *pointer_value1;
*pointer_value1 = *pointer_value2;
*pointer_value1 = swapper;
}

// prints the array in nice format, 10 numbers per line
void print (int numbers [])
{
int on_line, // number of values printed on the line
index; // index of current number being printed

on_line = 0;
// print each element in the array
for (index = 0; index < size; index++)
{
cout << setw (5) << numbers [index];
on_line++;
// if 10 numbers have been printed on the line
// go to next line
if (on_line == 10)
{
cout << "\n";
on_line = 0;
}
}
}