[Java] Problem with checking which key a user presses.

[c0rrupt]

I am writing a small Java console program. When I ask the user a question, they will answer with y or n. Only problem is that I can't get the program to detect which key the user pressed. Here is the code I am currently using but it isn't working. When I type y and press Enter it doesn't print anything, just another blank line and then the program exits.

System.out.println("Would you like to restart the calculator? [y/n] ");
Scanner userInput = new Scanner(System.in);
		
if (userInput.nextLine() == "y") {
	System.out.println("yes");
}

 

[zutme]

Heres how I would write it.

Scanner userInput = new Scanner(System.in);
String str="";
System.out.print("Would you like to restart the calculator? [y/n] ");  //not using println casue it looks weird to have prompt on next line
str=userInput.nextLine();

if (str.equalsIgnoreCase("y"))
{
System.out.println("\nyes");  // using "\n"  to move the cursor down to the next line because println wasnt used previously
}

 

[HorsePunchKid]

Be careful with ==. When you're comparing strings, you usually want to be using foo.equals(bar), which returns a boolean. The equality operator doesn't test the contents of the string, it just checks to see if the two string references point to the same object.

 

[Pyrolistical]

Ya, its the ==, use .equals(...) instead

 

[c0rrupt]

Anyone have any idea why this won't work. The d variables are double and userInput should always be an integer.

CostOfDrivingCalc.java:56: non-static variable dMilesDrivenDaily cannot be referenced from a static context
dMilesDrivenDaily = userInput.nextInt();
^
CostOfDrivingCalc.java:59: non-static variable dPriceGallonFuel cannot be referenced from a static context
dPriceGallonFuel = userInput.nextInt();
^
CostOfDrivingCalc.java:62: non-static variable dVehicleMileage cannot be referenced from a static context
dVehicleMileage = userInput.nextInt();
^
CostOfDrivingCalc.java:66: non-static variable cCustomValues cannot be referenced from a static context
cCustomValues = userInput.nextInt();
^

 

[HorsePunchKid]

This is one of those rare cases where the Java compiler is giving you a useful error message. You've got a static method, but your variables aren't declared as static (that is, you would have to have an instance of the class in order to use them).