Having some trouble with a assignment in c++ - c++

Question

I have a assignment I've been working on and my code is working but the results are off by a hair. I know the issue has to do with rounding but I just can't seem to figure out where the issue lies. I've included the assignment details as well as the results i'm getting versus the expected result. Any help is appreciated.
Link for images https://imgur.com/a/bqIcxfT
'''
// This program will display the size of a population for given number of years
// taking into account annual birth and death rates as well as the number of
// people who move away and move into the area.
#include <iostream>
#include <iomanip>
using namespace std;
//Function prototype
double calculatePop (double, double, double, int, int);
int main ()
{
double P; // Starting population
double B; // Annual birth rate
double D; // Annual death rate
int A; // Average number of people who arrive
int M; // Average number of people who move away
int nYears; // The number of years to display
cout << "This program calculates population change." << endl;
// Set numeric formatting
cout << setprecision(0) << fixed;
// Get starting population size
cout << "Enter the starting population size: ";
cin >> P;
while (P<2){
cout << "Starting population must be 2 or more.";
cout << "Please re-enter:";
cin >> P;}
// Get the annual birth rate
cout << "Enter the annual birth rate (as % of current population): ";
cin >> B;
while (B<0){
cout << "Birth rate percent cannot be negative.";
cout << "Please re-enter:";
cin >> B;}
B/=100;
// Get annual death rate
cout << "Enter the annual death rate (as % of current population): ";
cin >> D;
while (D<0){
cout << "Death rate percent cannot be negative.";
cout << "Please re-enter:";
cin >> D;}
D/=100;
// Get number of people who arrive
cout << "How many individuals move into the area each year? ";
cin >> A;
while (A<0){
cout << "Arrivals cannot be negative.";
cout << "Please re-enter:";
cin >> A;}
// Get number of people who move away
cout << "How many individuals leave the area each year? ";
cin >> M;
while (M<0){
cout << "Departures cannot be negative.";
cout << "Please re-enter:";
cin >> M;}
// Get number of years to see data for
cout << "For how many years do you wish to view population changes? " << endl << endl;
cin >> nYears;
while (nYears<1){
cout << "Years must be one or more.";
cout << "Please re-enter:";
cin >> nYears;}
cout << "Starting population: " << P << endl << endl;
//Display the population to user
for (int y=1; y<=nYears; y++)
{
P = calculatePop(P, B, D, A, M);
cout << "Population at the end of year " << y << " is " << P << ".\n";
}
}
double calculatePop (double P, double B, double D, int A, int M)
{
double N; //New Population Size
N = P + (B*P) - (D*P) + A - M;
return N;
}
'''

Answer 1

The value is correctly calculated but not outputted the same way as in the assignment. Setting setprecision(0) along with fixed will round the number to the nearest integer while the result shown in the assignment is the truncated number. To truncate the result, use
cout << "Population at the end of year " << y << " is " << int(P) << ".\n";