/* Test Function const and non-const parameter (FuncationConstParameter.cpp) */
#include <iostream>
using namespace std;

int squareConst(const int);
int squareNonConst(int);
int squareConstRef(const int &);
int squareNonConstRef(int &);

int main() {
   int number = 8;
   const int constNumber = 9;
   cout << squareConst(number) << endl;
   cout << squareConst(constNumber) << endl;
   cout << squareNonConst(number) << endl;
   cout << squareNonConst(constNumber) << endl;

   cout << squareConstRef(number) << endl;
   cout << squareConstRef(constNumber) << endl;
   cout << squareNonConstRef(number) << endl;
   // cout << squareNonConstRef(constNumber) << endl;
       // error: invalid initialization of reference of
       //  type 'int&' from expression of type 'const int'
}

int squareConst(const int number) {
   // number *= number;  // error: assignment of read-only parameter
   return number * number;
}

int squareNonConst(int number) {  // non-const parameter
   number *= number;
   return number;
}

int squareConstRef(const int & number) {  // const reference
   return number * number;
}

int squareNonConstRef(int & number) {  // non-const reference
   return number * number;
}