Passing functions as arguments to other functions to sort an array

[graceful oriole]

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[lunar moon]

!format

[graceful oriole]

bool (*comparisonFcn)(int, int);

COPY

    So,
    we’ll allow the caller to pass our sort routine a pointer to their desired
        comparison function as the third parameter,
    and then we’ll use the caller’s function to do the comparison.Here’s a full
            example of a selection sort that uses a function pointer parameter
                to do a user -
        defined comparison,
    along with an example of how to call it:

#include <utility>  #include <iostream>  void selectionSort(int* array, int size, bool (*comparisonFcn)(int, int)) {  for (int startIndex{ 0 }; startIndex < (size - 1); ++startIndex) { int bestIndex{ startIndex };  for (int currentIndex{ startIndex + 1 }; currentIndex < size; ++currentIndex) {  if (comparisonFcn(array[bestIndex], array[currentIndex])) { bestIndex = currentIndex; } }  std::swap(array[startIndex], array[bestIndex]); } } bool ascending(int x, int y) { return x > y;  }  bool descending(int x, int y) { return x < y;  }  void printArray(int* array, int size) { for (int index{ 0 }; index < size; ++index) { std::cout << array[index] << ' '; } std::cout << '\n'; } int main() { int array[9]{ 3, 7, 9, 5, 6, 1, 8, 2, 4 };  selectionSort(array, 9, descending); printArray(array, 9); selectionSort(array, 9, ascending); printArray(array, 9);

Oppenheimer

@lunar moon

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[lunar moon]

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