This program is just for two variables to be added up and display the results, but when I run it and input 2 and 2, it gives me 3.21412e-039.

Code:
#include <iostream>

using namespace std;

float calc(float a, float b, float c) {
      
      c = a + b;
      cin.get();
      return c;
}

int main() {
       float a;
       float b;
       float c;
       
       cout << "Input a number: ";
       cin >> a;
       cout << "Input a second number: ";
       cin >> b;
       calc(a, b, c);
       cout << a << " plus " << b << " equals " << c << " .\n";
       cin.get();
}