c++ - Radix Sorting algorithm difficulties -


i'm having problem understanding how pass user-input value parameter radix sorting algorithm.

enter image description here

my assignment class diagram shown here. can see, class constructor radixsort required take (int radix) , (int exponent). "radix" variable serves numerical base (i.e. base 10) , "exponent" used sort input numbers.

my code works perfectly, except 1 problem: works when input radix directly. here important parts of code:

radixsort(int radix, int exponent): sortroutine() { cout << "radix: " << radix << endl; cout << "exponent: " << exponent << endl; setradix(radix); setexponent(exponent); }  void sort(int array[], int size) {     cout << "-initiating radix sort-" << endl;     setsize(size);      int max = getmax(array, size);     int radix = getradix();     int * output = new int[size];      (int exponent = getexponent(); max / exponent > 0; exponent *= radix) {         radixalgorithm(array, size, radix, exponent, output);     } }  void radixalgorithm(int array[], int size, int radix, int exponent, int output[]) {      int i;     int count[10] = { 0 };      (i = 0; < size; i++)         count[(array[i] / exponent) % radix]++;      (i = 1; < radix; i++) {         count[i] += count[i - 1];     }      (i = size - 1; >= 0; i--) {         output[count[(array[i] / exponent) % radix] - 1] = array[i];         count[(array[i] / exponent) % radix]--;     }      (i = 0; < size; i++)         array[i] = output[i];      (i = 0; < size; i++) {         cout << array[i] << " ";     }     cout << endl; }

from can tell, things go wrong starting in radixalgorithm section:

int count[10] = { 0 };

i'm supposed able take radix user input. however, if try that, making this:

int count[radix] = { 0 };

i error:

array type 'int[radix]' not assignable.

expression did not evaluate constant.

because radix supposed user input, , therefore not constant, dont understand how use radix base of count[ ] array.

is there better way this? did make complicated? dont understand how i'm supposed perform radix sort in other way given i'm forced use form

radixsort( int radix, int exponent);

for constructor.

any advice or improved methods?

you're using

int * output = new int[size];

to allocate array of size known @ runtime. if understand that, can use same approach allocate int * count work same way. need initialize 0 yourself, , delete [] resulting array when finished.

you instead use std::vector patrick roberts suggested in comment, more appropriate way in c++, , has benefit of deallocating when goes out of scope:

std::vector<int> count(radix, 0);

int count[radix] variable length array, present in newer versions of c not c++ (see why aren't variable-length arrays part of c++ standard?).


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