Can the parameters of the C/C++ function be used without initialization?

#include <iostream> 
using namespace std;

int getsum(int);
int main() {

  int num, sum;
  cin >> num;
  sum = getsum(num);

  cout << "sum " << sum << endl;

}

int   getsum(int value) {
  int sum = 0;

  sum += value;
  return sum;
}