Question

我必须阅读以下格式。

因此，所有输入都用一行分隔。

我试过以下

   br = new Scanner(System.in);
   num = Integer.parseInt(br.next());
   while(br.hasNextInt()) {
        num = br.nextInt() ; 
        System.out.println(num);
    }

但它没有像我预期的那样工作。如果我输入第一个输入，它开始处理并打印。它不是在等我进入下一行。在C中，我可以使用sscanf。但在java中我不知道如何允许用户输入多行输入？请提出一些想法

Answer 1

您必须检查下一个可用输入，然后获取输入

br = new Scanner(System.in);
//num = Integer.parseInt(br.next());//remove this line
while(br.hasNextInt()) {//if number is avaialable
     num = br.nextInt(); //get that number
     System.out.println(num);
}

以下是sample code：

import java.util.Scanner;

class Ideone
{
    public static void main (String[] args)
    {
        Scanner sc = new Scanner(System.in);
        while(sc.hasNextInt())
            System.out.printf("input was: %d\n",sc.nextInt());
        sc.close();
    }
}

Answer 2

尝试

br = new Scanner(System.in); while (true) { int num = Integer.parseInt(br.nextLine()); System.out.println(num); }

Answer 3

   br = new Scanner(System.in);
   num = Integer.parseInt(br.next());
   br.nextLine();
     while(br.hasNextInt()) {
            num = br.nextInt() ; 
            br.nextLine();
            System.out.println(num);
        }

您需要添加br.nextLine();才能开始阅读下一行。

Answer 4

您所需要的并不完全明显，但是此代码（如下所示）将允许您阅读和存储多行输入，然后在您完成后将它们全部打印出来。

systemInScanner = new Scanner ( System.in ) ;

ArrayList < String > arrayListOfStrings = new ArrayList < > ( ) ; 

while ( systemInScanner . hasNextLine ( ) ) 
{
    arrayListOfStrings . add ( systemInScanner . NextLine ( ) ) ; 
}

for ( String line : input ) 
{
    System . out . println ( line ) ; 
}

Answer 5

如果你愿意逐行阅读。此代码逐行读取，并在输入空行时退出

br = new Scanner(System.in);
        int num=0;
        String input;
        input = br.nextLine();
        while(input.length()!=0) {
            num = Integer.parseInt(input);
            System.out.println(num);
            input = br.nextLine();
        }

Answer 6

你的问题并不完全清楚;但是，如果您尝试获取用户输入 - 然后再打印，则可以将输入保存到ArrayList。

import java.util.ArrayList;
import java.util.Scanner;
public class tu {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.println("Enter numbers, when you're done, enter a letter.");
        char firstLetter = '*';
        ArrayList<String> al = new ArrayList<>();
        while(!Character.isLetter(firstLetter)) {
            String input = "";
            boolean nullInput = false;
            do{
                if(nullInput)
                    System.out.println("Error; you can't enter an empty string.");
                nullInput = false;
                input = in.nextLine();
                if(input.length() == 0)
                    nullInput = true;
            }while(nullInput);
            firstLetter = input.charAt(0);
            al.add(input);
        }
        al.remove(al.size()-1);
        for(int i = 0; i < al.size(); i++) {
            System.out.println(); //creates newline in console
            System.out.println(al.get(i));

        }

    }


}

Answer 7

Scanner scanner = new.scanner(System.in);
String abc = scanner.next();
int a = scanner.nextInt();
scanner.close();

Answer 8

 br = new BufferedReader(new InputStreamReader(System.in));
        int ch;
        while ((ch = br.read()) != -1) {
            if (ch == 10) {
                System.out.println();
            }
        }

如何从控制台读取输入

8 个答案: