For Loop Returning A Range - for-loop

Question

my BlueJ project has 2 classes: StateProvince and Country. Below is the StateProvince class first, then the Country class where I'm at. I'm stuck on a method: "public int howManyHaveThisPopulation(int min, int max)" which takes the population in millions(e.g. 4, 6) and returns how many StateProvinces there are with populations in that range(e.g. 4-6 million, inclusive). I am not able to set it up and return the right answer. I would like help on how I can do this please. With how my method is now, the error message is that I'm missing a return statement. I know my method isn't correct. I have listed the class below and my progress on the method:
public class StateProvince
{
private String name; //e.g. "British Columbia" or "California"
private String capital; //e.g. "Victoria or "Sacramento"
private int populationInMillions; //e.g. 4 or 38
private final static int DEFAULT_POPULATION_MILLIONS = 4;
private final static String DEFAULT_STATE_PROVINCE = "British Columbia";
private final static String DEFAULT_CAPITAL = "Victoria";
public StateProvince()
{
}
/**
* constructor that takes in all 3 parameters and assigns them if they follow the rules:
* name: must be one of the 50 Unites States or 10 Canadian Provinces
* capital: must be the name of the capital city
* populationInMillions: must be between 0 and 38
*/
public StateProvince(String name, String capital, int populationInMillions)
{
if(isValidPopulation(populationInMillions) && (isValidStateProvince(name) &&
(isValidCapitalCity(capital))))
{
this.populationInMillions = populationInMillions;
this.name = name;
this.capital = capital;
}else
{
this.populationInMillions = DEFAULT_POPULATION_MILLIONS; //
this.name = DEFAULT_STATE_PROVINCE; //"British Columbia"
this.capital = DEFAULT_CAPITAL; //"Victoria"
}
}
//StateProvince p1 = new StateProvince("British Columbia", "Victoria", 5);
private boolean isValidStateProvince(String name)
{
String[] provinces = new String[10];
provinces[0] = "British Columbia";
provinces[1] = "Alberta";
provinces[2] = "Saskatchewan";
provinces[3] = "Manitoba";
provinces[4] = "Ontario";
provinces[5] = "Quebec";
provinces[6] = "PEI";
provinces[7] = "Newfoundland";
provinces[8] = "New Brunswick";
provinces[9] = "Nova Scotia";
for(int index = 0; index < provinces.length; index++)
{
if(provinces[index].equalsIgnoreCase(name))
{
return true;
}
index++;
}
return false;
}
private boolean isValidCapitalCity(String capital)
{
String[] capitals = new String[10];
capitals[0] = "Victoria";
capitals[1] = "Edmonton";
capitals[2] = "Regina";
capitals[3] = "Winnipeg";
capitals[4] = "Toronto";
capitals[5] = "Quebec City";
capitals[6] = "Charlottetown";
capitals[7] = "St. John's";
capitals[8] = "Fredericton";
capitals[9] = "Halifax";
for(int index = 0; index < capitals.length; index++)
{
if(capitals[index].equalsIgnoreCase(capital))
{
return true;
}
index++;
}
return false;
}
private boolean isValidPopulation(int populationInMillions)
{
if(populationInMillions >= 4 || populationInMillions <= 38)
{
return true;
}else
{
return false;
}
}
public void setName()
{
this.name = name;
}
public void setCapital()
{
this.capital = capital;
}
public String getName()
{
return name;
}
public String getCapital()
{
return capital;
}
public int getPopulationInMillions()
{
return populationInMillions;
}
public String getDetails()
{
return ("The capital of " + getName() + " (pop. " + populationInMillions + " million) is " + getCapital());
}
}
public class Country
{
private String country;
private StateProvince[] Canada;
public Country()
{
Canada = new StateProvince[10];
Canada[0] = new StateProvince("British Columbia", "Victoria", 4);
Canada[1] = new StateProvince("Alberta", "Edmonton", 3);
Canada[2] = new StateProvince("Saskatchewan", "Regina", 1);
Canada[3] = new StateProvince("Manitoba", "Winnipeg", 1);
Canada[4] = new StateProvince("Ontario", "Toronto", 13);
Canada[5] = new StateProvince("Quebec", "Quebec City", 8);
Canada[6] = new StateProvince("PEI", "Charlottetown", 0);
Canada[7] = new StateProvince("Newfoundland", "St. John's", 0);
Canada[8] = new StateProvince("New Brunswick", "Fredericton", 1);
Canada[9] = new StateProvince("Nova Scotia", "Halifax", 1);
}
public void displayAllStates()
{
for(int index = 0; index < Canada.length; index++)
{
if(Canada[0] != null)
{
System.out.println(Canada[index].getDetails());
}
index++;
}
}
public void addStateProvince(StateProvince stateProvince)
{
if(Canada != null)
{
for(int i = 0; i < Canada.length; i++)
{
if(Canada[i] == null)
{
Canada[i] = stateProvince;
return;
}
}
}
}
public int howManyHaveThisPopulation(int min, int max)
{
for(int i = 0; i < Canada.length; i++)
{
if(i > min && i < max)
{
return Canada[i].getPopulationInMillions();
}
}
}