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#include <iostream>
using namespace std;
int factorialNonRecursive (int n);
int factorialRecursive (int n);
int factorialNonRecursive (int n){
//non recursive version. need to use a loop
cout<< "Calling factorialNonRecursive." <<endl;
if(n < 0) {
cout<< "Warning! Factorial can only take non-negative input!" <<endl;
return 0;
}
if (n == 0) return 1;
int result = 1;
for(int i = 1; i <= n; i++){
result = result * i;
}
return result;
}
int factorialRecursive (int n){
//break it down into N * factorialRecursive(n-1)
cout<< "Calling factorialRecursive." <<endl;
if(n < 0) {
cout<< "Warning! Factorial can only take non-negative input!" <<endl;
return 0;
}
else if (n == 0) return 1;
else return ( n * factorialRecursive (n-1) );
}
int main() {
//test cases
/*
cout << factorialNonRecursive (-1) <<endl;
cout << factorialNonRecursive (0) <<endl;
cout << factorialNonRecursive (1) <<endl;
cout << factorialNonRecursive (4) <<endl;
cout << factorialNonRecursive (10) <<endl;
cout << factorialNonRecursive (100) <<endl;
cout << "===============================" <<endl;
*/
/*
cout << factorialRecursive (-1) <<endl;
cout << factorialRecursive (0) <<endl;
cout << factorialRecursive (1) <<endl;
cout << factorialRecursive (4) <<endl;
cout << factorialRecursive (10) <<endl;
cout << factorialRecursive (100) <<endl;
cout << "===============================" <<endl;
*/
return 0;
}
