C++ dynamic Initialization of objects

//it is long term fix deposit system
#include<iostream>
using namespace std;
class Fixed_deposit
{
long int pamount; // principal amount
int years; // peroid of investment
float rates; // rate of interest
float R_value; // return value of amount
public :
Fixed_deposit()
{
}
Fixed_deposit(long int p,int y,float r=0.12);
Fixed_deposit(long int p,int y,int r);
void display();
};
Fixed_deposit::Fixed_deposit(long int p, int y,float r)
{
pamount=p;
years=y;
rates=r;
R_value=pamount;
for(int i=1;i<=y;i++)
{
R_value=R_value*(1.0+r);
}
} Fixed_deposit::Fixed_deposit(long int p,int y, int r)
{
pamount=p;
years=y;
rates=r;
R_value=pamount;
for(int i=1;i<=y;i++)
{ R_value=R_value*(1.0+float(r)/100);
}
} void Fixed_deposit::display()
{
std::cout<<"\n";
std::cout<<"principal amount="<< pamount <<" \n";
std::cout << "return value="<<R_value<<"\n";
}
int main()
{
Fixed_deposit fd1,fd2,fd3; // deposit created
long int p; // for principal amount
int y; // investment periods years
float R; // interest rate, decimal form
int r; // interest rate, percentage form
std::cout <<"Enter amount, period, interest rate(in percentage)" << "\n";
std::cin >>p>> y>> R;
fd1=Fixed_deposit(p,y,R);
std::cout<<"Enter amount, period, interest rate(decimal form)" <<"\n";
std::cin>>p >>y >> r;
fd2=Fixed_deposit(p,y,r);
std::cout<<"Enter amount and period" << "\n";
std::cin>>p >> y;
fd3=Fixed_deposit(p,y);
std::cout <<"\nDeposit 1";
fd1.display();
std::cout <<"\n desposit 2";
fd2.display();
std::cout <<"\n deposit 3";
fd3.display();
}

the output of this program
enter amount, period, interest rate(in percentage)
10000 3 18
Enter amount, period, interest rate(in decimal form)
10000 3 0.18
Enter amount and period
10000 3



deposit 1
principal amount=10000
return value =16430.3
deposit 2
principal amount =10000
return value =16430.3


deposit 3
principal amount =10000
return value =14049.3