Reading inputs in java

问题

import java.io.*;
public class inputting {
/**
* @param args
* @throws IOException 
*/
public static void main(String[] args) throws IOException {
// TODO Auto-generated method stub
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println("number??");
String str;
     int i=0;
    while (i<5) {
            str=br.readLine();
            int n = Integer.parseInt(str);
            System.out.println(n);
        i++;}
}

}

if i want to read 5 integers how do i do that? what extra code i need to write?

回答1:

You should always use a Java Scanner to read inputs.

To your existing code, assuming String str = br.readLine(); makes str contain the line of at least one integer, eg. "10 20 30 40 50"

What you need to do is:

Scanner sc = new Scanner(str);
While (sc.hasNext())
{
   System.out.println(sc.nextInt());
   // ...or assign it to an array elment...your choice!
}

回答2:

If you want to ask multiple times the question number?? you just need to use a for or while loop around these three lines:

System.out.println("number??");
String  str = br.readLine();
int n = Integer.parseInt(str);

and add the read numbers to a list so you'd just need to change the last line.

回答3:

wrap your readline in a while loop that checks for user input to quit

        while ( !(str = br.readLine()).equalsIgnoreCase("q")) {
            int n = Integer.parseInt(str);
            System.out.println(n);
        }

来源：https://stackoverflow.com/questions/7101453/reading-inputs-in-java