初始化变量

Question

import java.util.Scanner; 

public class ExponentExperiment 
{ 
    public static void main(String [] args) 
    { 
     int numberOne; 
     int B; 
     int C; 
     Scanner keyBoard = new Scanner(System.in); 
     System.out.println("Enter an Integer"); 
     numberOne = keyBoard.nextInt(); 
     jordan(numberOne, B); 
     carter(numberOne, B, C); 
     System.out.println(numberOne + " squared is " + B); 
     System.out.println(numberOne + " cubed is " + C); 
    } 
    public static int jordan(int numberOne, int B) 
    { 
     B = numberOne * numberOne; 
    return B; 

    } 
    public static int carter(int numberOne, int B, int C) 
    { 
      C = B * numberOne; 
    return C; 

    } 

} 

错误：

H：\ ExponentExperiment.java：13：变量B可能还没有被初始化 约旦（的Numberone，B）; ^ H：\ ExponentExperiment.java：14：变量C可能未被初始化 卡特（numberOne，B，C）; ^ 2个错误

工具与退出代码完成1

Answer 1

，你必须INT B;和int C;在你的主要方法的顶部，做

int B = 0; 
    int C = 0; 

所以它们被初始化。

Answer 2

在Java中，简单类型的变量是按值传递的，所以它不会起作用。 参见：Is Java "pass-by-reference" or "pass-by-value"?

Answer 3

为什么你不使用你的返回值？

import java.util.Scanner; 

public class ExponentExperiment 
{ 
    public static void main(String [] args) 
    { 
     int numberOne; 
     int b = 0; 
     int c = 0; 
     Scanner keyBoard = new Scanner(System.in); 
     System.out.println("Enter an Integer"); 
     numberOne = keyBoard.nextInt(); 
     b = jordan(numberOne); 
     c = carter(numberOne, b); 
     System.out.println(numberOne + " squared is " + b); 
     System.out.println(numberOne + " cubed is " + c); 
    } 
    public static int jordan(int numberOne) 
    { 
     return (numberOne * numberOne); 
    } 

    public static int carter(int numberOne, int b) 
    { 
      return (b * numberOne); 
    } 
}