如何在单个命令行中输入两个值？

Question

I'm wondering how I can input two values through the terminal using only one command line. So instead of the user writing "5 {ENTER} 2 {ENTER}", it'd accept "5 2 {ENTER}" or "5, 2 {ENTER}".

Basically, how to make this:

System.out.println("Enter x value");
int x = inputScanner.nextInt();

System.out.println("Enter y value");
int y = inputScanner.nextInt();

into something that rather lets the user input both x and y on one line?

Answer 1

You can add this to your main() method:

public static void main(String[] args){
    int x = Integer.parseInt(args[0]);
    int y = Integer.parseInt(args[1]);

    //do something with x and y
}

and when you run it from the command line:

java your_class_name 5 2;

now x = 5 and y = 2

But i think you probably want to read the user input entered in 1 line. Then you can just do:

System.out.println("Enter x and y");
int x = inputScanner.nextInt();
int y = inputScanner.nextInt();

note that this will only work if user enters the input in the form 5 2 ie with a space in between. If you want a comma in between, ie 5,2 then you have to change the delimiter of the Scanner :

System.out.println("Enter x and y");

inputScanner.useDelimiter(",");

int x = inputScanner.nextInt();
int y = inputScanner.nextInt();

Answer 2

Another way to do this is to use main's arguments variable. (I am going to assume it is a jar file)

static void main (String[] args)

when the user runs the program using the following command:

java -jar thisjar.jar 5 2 

the 5 and 2 will be stored into the String[]. (arg[0] = 5) (arg[1] = 2). From there you can do:

int x = Integer.parseInt(arg[0]); //You have to parse the integer because it was stored as a string
int y = Integer.parseInt(arg[1]);

Answer 3

The way i would achieve this is to read in x and y into a String named xy and my then split them into a array like this.

System.out.println("Enter x and y values: ");
input = new Scanner(System.in); // Type the input like "x, y" (5, 5)
String xy = input.nextLine(); // Reads the x and y value as a string
String[] str = xy.split(","); // Takes the comma out and puts both values in the array
System.out.println("x: " + str[0] + ", y: " + str[1]); // the out looks like "x: 5, y: 5"

Answer 4

The command line argument answers are the easiest way to go, but if you want to do other things with the program before prompting the user for input, you're going to need to go another route. The way I would approach this is scan the input as a string, telling the user to separate the x and y values by a comma. Then, you can process the input, splitting it between the comma into x and y strings and checking to make sure x and y are integers (or floats), converting them into their desired types, or raising an error if the input was entered wrong. You would then have your two points for whatever the program is using them for. I used this approach in Python for a homework solver I used in my Algebra class last year. The code for this is pretty trivial so I'll let you take care of that part.