在 main() 方法中调用多个方法(int)

Question

我目前在我的主要方法中调用我的每个方法（int）时遇到问题，我的每个调用都收到错误“找不到变量”。如何修复我的代码，以便我可以调用每个方法并为每个单独的方法提供一个输出？这是我的代码：import java.util.*;public class Method{ public static void main(String [] args) {   System.out.println(evenOdd(x));  System.out.println(boxMake(n));  System.out.println(checkPrime(n));   } public static boolean evenOdd(int x) { Scanner sc = new Scanner(System.in);  System.out.println("Enter your number to check even or odd: "); x = sc.nextInt();  boolean odd = false;if(x % 2 ==0){odd = true;  System.out.println(odd + " is true."); }return odd;}public static void boxMake(int n) {Scanner sc = new Scanner(System.in);  System.out.println("Enter your number to make a box: ");n = sc.nextInt();for(int i=0; i<n; i++){  for(int x=0; x<n; x++){     System.out.print("*");   }     System.out.println("");  }} public static int checkPrime(int n){ int i; int m=0; int flag=0; Scanner sc = new Scanner(System.in);   System.out.println("Enter a number to check if prime: "); n = sc.nextInt(); m=n/2;  if(n==0||n==1){     System.out.println(n + " is not a prime number");  }else{     for(i=2; i<=m; i++){        if(n % i == 0){           System.out.println(n + " is not a prime number");           flag = 1;        break;        }      }        if(flag == 0){           System.out.println(n + " is a prime number");         }     }      return n;   }}

Answer 1

请将您的代码修改为：

public class Example {

    public static void main(String[] args) {

        int x = 0, n = 0, p = 0;

        Scanner sc = new Scanner(System.in);

        System.out.println("Enter your number to check even or odd: ");

        x = sc.nextInt();

        evenOdd(x);

        System.out.println("Enter your number to make a box: ");

        n = sc.nextInt();

        boxMake(n);

        System.out.println("Enter a number to check if prime: ");

        p = sc.nextInt();

        checkPrime(p);

        sc.close();

    }

    public static void evenOdd(int x) {

        if (x % 2 == 0) {

            System.out.println(x + " is even.");

            return;

        }

        System.out.println(x + " is odd.");

    }

    public static void boxMake(int n) {

        for (int i = 0; i < n; i++) {

            for (int x = 0; x < n; x++) {

                System.out.print("*");

            }

            System.out.println("");

        }

    }

    public static void checkPrime(int n) {

        int i;

        int m = 0;

        int flag = 0;

        m = n / 2;

        if (n == 0 || n == 1) {

            System.out.println(n + " is not a prime number");

        } else {

            for (i = 2; i <= m; i++) {

                if (n % i == 0) {

                    System.out.println(n + " is not a prime number");

                    flag = 1;

                    break;

                }

            }

            if (flag == 0) {

                System.out.println(n + " is a prime number");

            }

        }

    }

}

Answer 2

n并且x是您方法中的局部变量。请记住，例如nfrom与fromevenOdd()相同，除了名称之外什么都没有。如果你想在你的类中使用并且将它们定义为类成员。nboxMake()nx

import java.util.*;

public class Method{

private int n;

private int x;

Answer 3

使 main 方法看起来像这样，并从您的方法中删除 Scanners，如下所示：

 public static void main(String [] args) { 

      Scanner sc = new Scanner(System.in);

      System.out.println("Enter your number to check even or odd: ");

      x = sc.nextInt();

      System.out.println("Enter your number to make a box: ");

      n = sc.nextInt();

      System.out.println(evenOdd(x));

      System.out.println(boxMake(n));

      System.out.println(checkPrime(n));  

     }

public static boolean evenOdd(int x) {

  boolean odd = false;

if(x % 2 ==0){

odd = true;

  System.out.println(odd + " is true.");

 }

return odd;

}

public static void boxMake(int n) {

for(int i=0; i<n; i++){

  for(int x=0; x<n; x++){

     System.out.print("*");

   }

     System.out.println("");

  }

}

 public static int checkPrime(int n){

 int i;

 int m=0;

 int flag=0;

 m=n/2;

  if(n==0||n==1){

     System.out.println(n + " is not a prime number");

  }else{

     for(i=2; i<=m; i++){

        if(n % i == 0){

           System.out.println(n + " is not a prime number");

           flag = 1;

        break;

        }

      }

        if(flag == 0){

           System.out.println(n + " is a prime number"); 

        }

     }

      return n;

   }

}