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// FILE: select.cxx
// An interactive test program for the selectionsort function
#include <algorithm> // Provides swap
#include <cstdlib> // Provides EXIT_SUCCESS, size_t
#include <iostream> // Provides cout and cin
using namespace std;
// PROTOTYPE of the function used in this test program:
void selectionsort(int data[ ], size_t n);
// Precondition: data is an array with at least n components.
// Postcondition: The elements are rearranged so that
// data[0] <= data[1] <= ... <= data[n-1].
int main( )
{
const char BLANK = ' ';
const size_t ARRAY_SIZE = 10; // Number of elements in the array to be sorted
int data[ARRAY_SIZE]; // Array of integers to be sorted
int user_input; // Number typed by the user
size_t number_of_elements; // How much of the array is used
size_t i; // Array index
// Provide some instructions.
cout << "Please type up to " << ARRAY_SIZE << " positive integers. ";
cout << "Indicate the list's end with a zero." << endl;
// Read the input numbers.
number_of_elements = 0;
cin >> user_input;
while ((user_input != 0) && (number_of_elements < ARRAY_SIZE))
{
data[number_of_elements] = user_input;
number_of_elements++;
cin >> user_input;
}
// Sort the numbers, and print the result with two blanks after each number.
selectionsort(data, number_of_elements);
cout << "In sorted order, your numbers are: "<< endl;
for (i = 0; i < number_of_elements; i++)
cout << data[i] << BLANK << BLANK;
cout << endl;
return EXIT_SUCCESS;
}
void selectionsort(int data[ ], size_t n)
// Library facilities used: algorithm, cstdlib
{
size_t i, j, index_of_largest;
int largest;
if (n == 0)
return; // No work for an empty array.
for (i = n-1; i > 0; --i)
{
largest = data[0];
index_of_largest = 0;
for (j = 1; j <= i; ++j)
{
if (data[j] > largest)
{
largest = data[j];
index_of_largest = j;
}
}
swap(data[i], data[index_of_largest]);
}
}
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