Question

所以这段代码要求输入一个名字和数字1-20，但是如果你输入的数字超过20或者低于1，程序仍会运行，我知道我需要一个条件语句来计算＆＃的数量34; ANO＆＃34;停止并重新询问该声明并重新运行该段，但我不知道如何将其实现到代码中。

＆＃13;

// library - for interactive input
import java.util.Scanner;

//---------------------------------
// program name header
public class feb24a
{
  //--------FUNCTION CODING ---------------
  // FUNCTION HEADER
  public static void seeit(String msg, String aname, int ano)
  {
    // statement to accomplish the task of this function
    System.out.print("\n The message is " + msg + "\t" + "Name is:" + aname + "\t" + "number is: " + ano);
    // return statement without a variable name because it is a void
    return;
  }

  //-------------------  MAIN MODULE CODING TO CALL FUNCTIONS ----------------
  // Main module header
  public static void main (String[] args) 
  {          
    String msg, aname;
    int ano, again, a, b;

    msg = "Hello";
    a = 1;
    b = 20;

    //Loop control variable
    again = 2;    	    	 
    while(again == 2)
    {
       System.out.print("\n enter NAME: ");    	 
       Scanner username = new Scanner(System.in);
	 
       aname = username.nextLine();
	 
       System.out.print("\n enter number 1-20: ");    	 
       Scanner userno = new Scanner(System.in);
	 
       ano = userno.nextInt();
       seeit(msg, aname, ano);
	
       //ask user if they want to do it again, 2 for yes any other for no
       System.out.print("\n do you want to do this again? 2 for yes ");
	 
       Scanner useragain = new Scanner(System.in);    	 
       again = useragain.nextInt();
     } //terminate the while loop
   }    	
 }

＆＃13;

Answer 1

尝试在while循环中包围ano = userno.nextInt（）。（即，while（ano＆lt; 1 || ano＆gt; 20））并在while循环中放入提示。这样，它将继续读取一个新的数字，直到它最终不再满足while循环并且将会爆发。

Answer 2

用这个替换你的while循环：

    Scanner scanner = new Scanner(System.in);
    while (again == 2) {
        ano = 0;

        System.out.print("\n enter NAME: ");
        aname = scanner.nextLine();

        while (ano < 1 || ano > 20) {
            System.out.print("\n enter number 1-20: ");
            ano = scanner.nextInt();
        }

        seeit(msg, aname, ano);

        System.out.print("\n do you want to do this again? 2 for yes ");
        again = scanner.nextInt();
    }

如何在此程序中设置条件语句？

2 个答案: