JAVA初学者帮助需要在循环中输入字符串

Question

im a beginner in Java, and i have a problem to do: the problem prompts the user 5 times to enter, the Name of a stock then the Share Price then the number of shares owned and we should calculate the sum of all the stock values, i wrote it using only two prompts using a loop, but my issue is that, in the second prompt time the loop Skips the String input for the second Name of stock instead of promting...bellow is the code:

import java.util.Scanner;
public class test1 {

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        double sharePrice =0,stockPrice = 0, temp = 0 ;
        int i = 0;
        double sum=0;
        String name;
        while (i < 2) {
            System.out.println("Enter the Name of the Stock "); 
            name = input.nextLine();

            System.out.println("Enter the Share price ");
            sharePrice = input.nextDouble();

            System.out.println("Enter the number of owned shares");
            int numberOfshares = input.nextInt();
            stockPrice = sharePrice * (double)(numberOfshares);

            sum += stockPrice;

            i++;
        }
        System.out.println("the total stockprice owned is: " + sum );
    }
}

And this is the output i get:

  Enter the Name of the Stock 
  nestle
  Enter the Share price 
  2
  Enter the number of owned shares
  4


  Enter the Name of the Stock 
  Enter the Share price

What makes the input skip during the second loop?

Answer 1

Again as per my comment the problem is that your code doesn't handle the End Of Line (EOL) token when calling nextInt() or nextDouble() .

The solution is to use input.nextLine() after getting your int and double in order to swallow the EOL token:

sharePrice = input.nextDouble();
input.nextLine();  // add this 

System.out.println("Enter the number of owned shares");
int numberOfshares = input.nextInt();
input.nextLine();  // add this 
stockPrice = sharePrice * (double)(numberOfshares);

Answer 2

The problem is that the last time you call

int numberOfshares = input.nextInt();

in the first iteration of the loop your first passes a carriage return as the next stock name. You could instead use:

double sharePrice = Double.parseDouble(input.nextLine());

and

int numberOfshares = Integer.parseInt(input.nextLine());

Answer 3

You should readout the newline characters after reading the share price and number of shares:

public static void main(String[] args)
{
    Scanner input = new Scanner(System.in);
    double sharePrice = 0, stockPrice = 0;
    int i = 0;
    double sum = 0;
    String name;
    while (i < 2)
    {
        System.out.println("Enter the Name of the Stock ");
        name = input.nextLine();
        System.out.println("Enter the Share price ");
        sharePrice = input.nextDouble();
        // Read out the newline character after the share price.
        input.nextLine();
        System.out.println("Enter the number of owned shares");
        int numberOfshares = input.nextInt();
        // Read out the newline character after the number of shares.
        input.nextLine();
        stockPrice = sharePrice * (double) (numberOfshares);
        sum += stockPrice;
        System.out.println(String.format("Name: %s, Price: %f, Shares: %d, Total: %f",
                                         name,
                                         sharePrice,
                                         numberOfshares,
                                         stockPrice));
        i++;
    }
    System.out.println("the total stockprice owned is: " + sum);
}

See the lines with comments above: