java这里有什么错误？

Question

import java.util.Scanner;
public class program4
{
public static void main(String args[])
{
Scanner input = new Scanner(System.in);


System.out.println(" Hello and welcome to the program ");
System.out.println("Enter your number.");



int number = input.nextInt();
int integerDoubled; 


System.out.println("Your result is" + doubleNumber(number));
System.out.println(" thank you for using my program ");
}

public static int doubleNumber (int x){
int integerDoubled;
return integerDoubled  = (x*2);

}

if (integerDoubled < 100 ); {
less_100(integerDoubled);

} else if ; 

greater_100(integerDoubled);



public static int less_100 (int integerDoubled)
{
   int integerDoubled;
  return integerDoubled =(x*2);
  } 
 public static int greater_100 (int integerDoubled) 
 {
  int integerDoubled;
    return integerDoubled =(x*3);
   }


}
    }

我认为错误在If语句中，但我不知道如何修复它。 我知道integerDoubled是一个局部变量，我应该把它设为全局变量，但我不知道怎么做。我应该把if语句和doubleNumber函数放在一起吗

Answer 1

我试着理解你的计划这就是我想到的

 import java.util.Scanner;
public class T
{   

    public static int doubleNumber (int x){
        int integerDoubled;
        return integerDoubled  = (x*2);
    }



    public static void main(String args[])
    {
        Scanner input = new Scanner(System.in);


        System.out.println(" Hello and welcome to the program ");
        System.out.println("Enter your number.");



        int number = input.nextInt();
        int integerDoubled=doubleNumber(number); 


        System.out.println("Your result is" + integerDoubled);
        System.out.println(" thank you for using my program ");
        if (integerDoubled < 100 ) {
            less_100(integerDoubled);

        } 
        else
            greater_100(integerDoubled);
    }






    public static int less_100 (int integerDoubled)
    {

        return integerDoubled =(integerDoubled*2);
    } 
    public static int greater_100 (int integerDoubled) 
    {

        return integerDoubled =(integerDoubled*3);
    }



}

Answer 2

如果格式化了代码（IDE将为您执行此操作），您将看到if语句并不像必须的那样位于方法内部。如果您正确地使用IDE，那么查找和纠正此类错误的速度会快得多，而且您几乎不需要考虑它