C++ Passing user input to a parameter for a constructors

Here is in C++ Passing user input to a variable to a parameter for a function in. But I need pass parameters from user for constructor parameters. Please help me with simple example. Don't have to be same as mine, you can do all different but I just need it.

#include <iostream>
#include <cmath>

using namespace std;

float stockMarketCalculator(float p, float r, int t){
  float a;

  for(int day = 1; day <=t; day++){
    a = p * pow(1+r, day);
    cout << a << endl;
  }

}

int main()
{
  float p;
  float r;
  int t;

  cout << "Please enter the principle" << endl;
  cin >> p >> endl;

  cout << "Please enter the rate" << endl;
  cin >> r >> endl;

  cout << "Please enter the time in days" << endl;
  cin >> t >> endl;
  cout << stockMarketCalculator(p, r, t);

  return 0;
}