如何从java中的一行读取多个输入？

Question

So i have this code :

for(int i=0;i<number;i++) { 
System.out.println("WHAT HOUSEHOLD DO YOU WANT TO CONNECT IN APARTMENT NO."+(i+1));
        System.out.println("1 ) OVEN");
        System.out.println("2 ) TV");
        System.out.println("3 ) VACCUUM CLEANER");
        System.out.println("4 ) REFRIGERATOR");
        int option = cin.nextInt();
        switch(option) {
        case 1: {
            for(initiereAparate e : aparate)
            fw.write((i+1)+" "+e.ob1.denumire+" "+e.ob1.material+" "+e.ob1.culoare+" "+e.ob1.origine+" "+e.ob1.consumEnergie+"\r\n"); break;
        }
        case 2: {
            for(initiereAparate e : aparate)
            fw.write((i+1)+" "+e.ob2.denumire+" "+e.ob2.material+" "+e.ob2.culoare+" "+e.ob2.origine+" "+e.ob2.consumEnergie+"\r\n"); break;
        }
        case 3: {
            for(initiereAparate e : aparate)
            fw.write((i+1)+" "+e.ob3.denumire+" "+e.ob3.material+" "+e.ob3.culoare+" "+e.ob3.origine+" "+e.ob3.consumEnergie+"\r\n"); break;
        }
        case 4: {
            for(initiereAparate e : aparate)
            fw.write((i+1)+" "+e.ob4.denumire+" "+e.ob4.material+" "+e.ob4.culoare+" "+e.ob4.origine+" "+e.ob4.consumEnergie+"\r\n"); break;
        }
        }
}

I would like to know how to read multiple inputs.For example i will type in one line 1 2 4 , and this numbers will execute 3 cases at once.In my code that i already have i can type only 1 number and it will execute only one case statement

Answer 1

You would need to change your input function to expect a string rather than an int. And then simply split your string into number and loop trought the number to execute your switch case.

PS please note that this code is untested, don't just copy and paste it expecting everything to work perfectly. Try to understand what I did and apply it to your own context.

for (int i = 0; i < number; i++) {
        System.out.println("WHAT HOUSEHOLD DO YOU WANT TO CONNECT IN APARTMENT NO." + (i + 1));
        System.out.println("1 ) OVEN");
        System.out.println("2 ) TV");
        System.out.println("3 ) VACCUUM CLEANER");
        System.out.println("4 ) REFRIGERATOR");
        // we change this to nextLine() because we want a string.
        String option = cin.nextLine();
        // we split our string at white space, this give us an array of string;
        String[] options = option.split("\\s+");
        // we parse every options in the array
        for (int j = 0; j < options.length; j++) {
            // we need to cast the option back to an integer since, it's what we are
            // comparing.
            int currentOption = Integer.parseInt(options[j]);
            switch (currentOption) {
            case 1: {
                for (initiereAparate e : aparate)
                    fw.write((i + 1) + " " + e.ob1.denumire + " " + e.ob1.material + " " + e.ob1.culoare + " "
                            + e.ob1.origine + " " + e.ob1.consumEnergie + "\r\n");
                break;
            }
            case 2: {
                for (initiereAparate e : aparate)
                    fw.write((i + 1) + " " + e.ob2.denumire + " " + e.ob2.material + " " + e.ob2.culoare + " "
                            + e.ob2.origine + " " + e.ob2.consumEnergie + "\r\n");
                break;
            }
            case 3: {
                for (initiereAparate e : aparate)
                    fw.write((i + 1) + " " + e.ob3.denumire + " " + e.ob3.material + " " + e.ob3.culoare + " "
                            + e.ob3.origine + " " + e.ob3.consumEnergie + "\r\n");
                break;
            }
            case 4: {
                for (initiereAparate e : aparate)
                    fw.write((i + 1) + " " + e.ob4.denumire + " " + e.ob4.material + " " + e.ob4.culoare + " "
                            + e.ob4.origine + " " + e.ob4.consumEnergie + "\r\n");
                break;
            }
        }
    }
}

As Arvind Kumar Avinash pointed out in the comment, it is important to add the keyword break to you switch cases, this ensure that you only treat one case per iteration.

Answer 2

Yes, you can do that. You can use following idea:

String option = cin.nextLine();
String[] data=option.split(" ") // split by space character
for(int i=0;i<data.length;i++){
int option = Integer.parseInt(data[i]);
switch(option)...}