My instructor wishes for me to construct prototypes for a small program but I'm having a time figuring this out. help please.

// interest.cpp

// Date: Feb 25, 2008

// Calculate the simple interest on a loan for 1 year given the amount and rate

#include<iostream>

#include<iomanip>

using namespace std;

Code:

//Prototypes here

int main()

{

// declare variables

// get user input

// call function for calculation

// display results

return 0;

}

double calcint(double amount, double rate)

{

return amount * rate * 1;

}