how to increment population/neverending loop - c++

Question

I'm a beginner who has some questions relating to my homework for school.
With my current code I'm stuck in a neverending loop which I'm assuming is because my condition is never actually met (Pop A being greater than Pop B) and I'm unsure how to move on. I'm also not sure how to properly increment/calculate the years needed for Town A to surpass Town B but this is what I've got so far.
#include <iostream>
#include <iomanip>
using namespace std;
int main()
{
int townA;
int townB;
double growthA;
double growthB;
double finalA;
double finalB;
int years = 0;
cout << "Enter the population of town A: ";
cin >> townA;
cout << "Enter the growth rate of town A: ";
cin >> growthA;
cout << "Enter the population of town B: ";
cin >> townB;
cout << "Enter the growth rate of town B: ";
cin >> growthB;
while ((townA <= 0) && (growthA <=0) && (townB > townA) && (growthB < growthA) && (growthB > 0))
{
cout << "Error: Values must be positive, please try again." << endl;
cout << "Enter the population of town A: ";
cin >> townA;
cout << "Enter the growth rate of town A: ";
cin >> growthA;
cout << "Enter the population of town B: ";
cin >> townB;
cout << "Enter the growth rate of town B: ";
cin >> growthB;
cout << endl;
}
years = 0;
while (townA <= townB)
{
finalA = ((growthA / 100) * (townA)) + townA;
finalB = ((growthB / 100) * (townB)) + townB;
cout << "It took Town A " << years << " years to exceed the population of Town B." << endl;
cout << "Town A " << finalA << endl;
cout << "Town B " << finalB << endl;
}
cout << "\n\n" << endl; // Teacher required us to output it to the screen incase anyone is wondering why I have this block
cout << setw(3) << "Town A" << setw(15) << "Town B" << endl;
cout << setw(3) << growthA << "%" << setw(10) << growthB << "%" << endl;
cout << setw(3) << townA << setw(7) << townB << endl;
cout << "Year" << endl;
cout << "--------------------------------------------" << endl;
return 0;
}

Answer 1

You are not updating the values of townA and townB in the loop. Hence, you never get out of the loop.
Also, you need to increment years in the loop. Use:
while (townA <= townB)
{
finalA = ((growthA / 100) * (townA)) + townA;
finalB = ((growthB / 100) * (townB)) + townB;
cout << "Town A " << finalA << endl;
cout << "Town B " << finalB << endl;
// Update the values of the key variables.
++years;
townA = finalA;
townB = finalB;
}
// This needs to be moved from the loop.
cout << "It took Town A " << years << " years to exceed the population of Town B." << endl;