如何在 java 中使用 nextLine 进行扫描仪

Question

I used correct data type but I cant find my errors. Below is my code;

Scanner input = new Scanner (System.in);
    
    //Read 
    System.out.printf ("Enter the station: ");
    String s  = input.nextLine();
    
    System.out.printf ("Enter quantity in liter: ");
    double q  = input.nextDouble();

    
    System.out.printf ("Enter type of petrol: ");
    String t  = input.nextLine();
    
    System.out.printf ("Enter price of petrol: ");
    double p  = input.nextDouble();
    
    System.out.printf ("Enter discount: ");
    int d  = input.nextInt();

when I run my program, It does not go to next line to input values. For petrol type, I want to input something like "Super 99" so I need to use input.nextLine() but its not working.

Answer 1

Try the below code.

Use another input.nextLine() right after the double q = input.nextDouble(); line.

public static void main(String[] args) {
        Scanner input = new Scanner (System.in);

        //Read
        System.out.printf ("Enter the station: ");
        String s  = input.nextLine();

        System.out.printf ("Enter quantity in liter: ");
        double q  = input.nextDouble();
        input.nextLine();

        System.out.printf ("Enter type of petrol: ");
        String t  = input.nextLine();

        System.out.printf ("Enter price of petrol: ");
        double p  = input.nextDouble();

        System.out.printf ("Enter discount: ");
        int d  = input.nextInt();
    }

Answer 2

/* *****This will work for you dear */

import java.util.*; class Tester {

    public static void main(String[] args)
  {
    Scanner input = new Scanner (System.in);
    System.out.printf ("Enter the station: ");
    String s  = input.nextLine();
    
    System.out.printf ("Enter quantity in liter: ");
    double q  = input.nextDouble();

    input.nextLine();
    System.out.printf ("Enter type of petrol: ");
    String t  = input.nextLine();
    
    System.out.printf ("Enter price of petrol: ");
    double p  = input.nextDouble();
    
    System.out.printf ("Enter discount: ");
    int d  = input.nextInt();
   }

}

Answer 3

You just need to use:

System.out.println("Enter the type of petrol");

It will work like this:

Enter the type of petrol
Super99     //its what you will enter as per your choice here the cursor will automatically take you to the next line

Answer 4

To print a line including a newline:

System.out.println("Enter price of petrol: ");
// -OR-
System.out.printf("Enter price of petrol: \n");

To obtain a single token (a single word, number, integer, etc):

scanner.nextInt(); // integer
scanner.next(); // word

To obtain an entire line:

scanner.useDelimiter("\r?\n");
// now the scanner is in 'entire line' mode
scanner.nextInt(); // still works
scanner.next(); // gets one line's worth

To go back to 'one token per whitespace' mode, where entering eg "abc" (enter) will cause 3 .next() calls of data to be available:

scanner.reset();
// -OR-
scanner.useDelimiter("\s+");

TIP: Don't mix nextLine() and any other next method.