The reason you are getting the error is that some execution paths in your code do not set a value to hours. It is difficult to see this problem because you are mixing input validation with result calculation logic.
You could just initialize hours to 0, but I suspect that your program still won’t work the way you expect.
While there are many ways to solve this problem, I would recommend breaking the code into a number of smaller parts to solve each problem individually. There are a number of advantages to this, including being able to test each piece separately, and making it easier to understand and, more importantly, maintain each piece.
If you separate each piece into it’s own method, your main method could look something like this:
public static void main(String[] args) {
int plan = getPlanFromUser();
int month = getMonthFromUser();
int hours = getHoursFromUser(month);
evaluateSavings(plan, month, hours);
}
Then to get the plan from the user, you write a method called getPlanFromUser() that retrieves the user’s input and validates it before returning a valid selection.
Likewise with the other ‘get’ methods, with the special case being getHoursFromUser() where you pass the month so that the method can validate that the correct hours are entered.
Finally, your evaluateSavings() method receives all the users input (which has already been validated) and simply calculates the appropriate savings.
Taking this kind of approach means that you only have to solve a couple of problems in each method, and you don’t have to think about everything at the same time.
EDIT: Here’s the code reorganised as described above
import java.util.Scanner;
public class HW04P05 {
private static final int PACKAGE_1 = 1;
private static final int PACKAGE_2 = 2;
private static final int PACKAGE_3 = 3;
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int plan = getPlan(input);
int month = getMonth(input);
int hours = getHours(input, month);
calculateSavings(plan, hours);
}
private static int getPlan(Scanner input) {
// packages menu
System.out.println();
System.out.println("[1] Package 1: $15.95 a month for up to 10 hours of service. Additional hours are $2.00 per hour.");
System.out.println("[2] Package 2: $20.95 a month for up to 20 hours of service. Additional hours are $1.00 per hour.");
System.out.println("[3] Package 3: $30.99 per month unlimited access.");
System.out.println();
System.out.print("Enter [1 - 3] for select your package: ");
// get input
int choice = input.nextInt();
// input validation
System.out.println(" ");
if (choice < 0) {
exitProgram("The menu choice cannot be negative, must be a value [1 - 3]");
} else if (choice == 0) {
exitProgram("The menu choice cannot be zero, must be a value [1 - 3]");
} else if (choice > 3) {
exitProgram("The menu choice must be a value [1 - 3]");
}
return choice;
}
private static int getMonth(Scanner input) {
// month menu
System.out.println("[1] January [4] April [7] July [10] October");
System.out.println("[2] February [5] May [8] August [11] November");
System.out.println("[3] March [6] June [9] September [12] December");
System.out.println("");
System.out.print("Enter [1 - 12] for select billed month: ");
// get input
int month = input.nextInt();
// input validation
if (month < 0) {
exitProgram("The month cannot be negative, must be a value [1 - 12]");
} else if (month == 0) {
exitProgram("The month cannot be zero, must be a value [1 - 12]");
} else if (month > 12) {
exitProgram("The month must be a value [1 - 12]");
}
return month;
}
private static int getHours(Scanner input, int month) {
// hours menu
System.out.println(" ");
System.out.print("Enter the number of hours the plan package was used: ");
// get input
int hours = input.nextInt();
// input validation
if (hours < 0) {
exitProgram("ERROR: The number of hours cannot be negative.");
}
if ((month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12) && hours > 744) {
exitProgram("ERROR: The number of hours cannot be higher than 744 on the month selected.");
}
if ((month == 4 || month == 6 || month == 9 || month == 11) && hours > 720) {
exitProgram("ERROR: The number of hours cannot be higher than 720 on the month selected.");
}
if (month == 2 && hours > 672) {
exitProgram("ERROR: The number of hours cannot be higher than 672 on the month selected.");
}
return hours;
}
private static void calculateSavings(int plan, int hours) {
double pricePlan1 = calculatePricePlan1(hours);
double pricePlan2 = calculatePricePlan2(hours);
double pricePlan3 = 30.99;
switch(plan) {
case PACKAGE_1:
System.out.println(String.format("The cost of your bill is: $%.2f", pricePlan1));
if (pricePlan1 > pricePlan2) {
System.out.println(String.format("On package 2 you could have saved $%.2f", pricePlan1 - pricePlan2));
}
if (pricePlan1 > pricePlan3) {
System.out.println(String.format("On package 3 you could have saved $%.2f", pricePlan1 - pricePlan3));
}
break;
case PACKAGE_2:
System.out.println(String.format("The cost of your bill is: $%.2f", pricePlan2));
if (pricePlan2 > pricePlan3) {
System.out.println(String.format("On package 3 you could have saved $%.2f", pricePlan2 - pricePlan3));
}
break;
case PACKAGE_3:
System.out.println(String.format("The cost of your bill is: $%.2f", pricePlan3));
break;
}
}
private static double calculatePricePlan1(int hours) {
if (hours <= 10) {
return 15.95;
}
return 15.95 + ((hours - 10) * 2);
}
private static double calculatePricePlan2(int hours) {
if (hours <= 20) {
return 20.95;
}
return 20.95 + (hours - 20);
}
private static void exitProgram(String reason) {
System.out.println(reason);
System.out.println("The program will now exit.");
System.exit(1);
}
}
Note that each method fits on one ‘page’ and each can be understood and tested independently. This approach makes it much easier for other developers to understand what the code does (and therefore reduces maintenance cost).
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solved Java: ERROR variable scopes in if statements