Java 扫描仪合并线

Question

I am trying to use a for loop to ask for 3 pieces of user input which are then used to create a new instance of a class. It works for the first loop, but then the second loop I get this prompt on the console and it expects an integer input.

Enter the employee's name: adam
Enter their hours worked: 1
Enter the employee's pay rate: 1
Enter the employee's name: Enter their hours worked: 

The code to input the data looks like this:

for (int i = 0; i < 5; i++) {
            System.out.print("Enter the employee's name: ");
            String employeeName = input.nextLine();
            System.out.print("Enter their hours worked: ");
            int hoursWorked = input.nextInt();
            System.out.print("Enter the employee's pay rate: ");
            double payRate = input.nextDouble();
            employee[i] = new Payroll(employeeName, hoursWorked, payRate);

I saw other questions on this site that suggest I use input.next() instead of input.nextLine() but that solution did not work either. How do I get the input lines to separate like they should?

Answer 1

The problem is here:

 double payRate = input.nextDouble();

With nextDouble , the scanner just stops when finishes reading the double value, skipping the rest of the line, including \n .

The second time the nextLine() is called, it just reads the end of the double input you entered before, and continues with " Enter their hours worked ", setting the employeeName empty after the first iteration.

As it is, your code could only work if you enter the value of the rate separated by the following employee name, like this (ugly):

  Enter the employee's pay rate: 3559 James

Make the scanner force reading the end of the "double" line at the end of the loop:

for (int i = 0; i < 5; i++) 
{
    System.out.print("Enter the employee's name: ");
    String employeeName = input.nextLine();
    System.out.print("Enter their hours worked: ");
    int hoursWorked = input.nextInt();
    System.out.print("Enter the employee's pay rate: ");
    double payRate = input.nextDouble();
    employee[i] = new Payroll(employeeName, hoursWorked, payRate);
      
    //this
    if (i<4)
      input.nextLine();
}