找不到符号变量java

我试图在

Java

中编写以下程序，其中我编写了一个递归和迭代方法，以计算从

n

到

m

的所有奇数之和

导入java.util.Scanner

公共类分配Q7{

public static int recursivesum(int n, int m){

    if (n < m){
        int s = n;
        s += recursivesum(n+2, m);

    } else{
        if(m < n){
            int  s = m;
            s += recursivesum(m+2, n);

        }
    }
    return s;
}

public static int iterativesum(int n, int m){
    if(n < m){
        int s = n;
        for(int i = n; i <= m; i += 2){
            s += i; 
                    return s;
        }
    } else
        if(m < n){
            int s = m;
            for(int i = m; i <= n; i += 2){
            s += i; 
                    return s;
            }
        }

}

public static void main(String args[]){

    int n,m;

    Scanner in = new Scanner(System.in);

    System.out.println("Enter two numbers: ");
    n = in.nextInt();
    m = in.nextInt();

    while(n%2 == 0){
        System.out.println("Enter the first number again: ");
        n = in.nextInt();
    }

    while(m%2 == 0){
        System.out.println("Enter the second number again: ");
        m = in.nextInt();
    }

    System.out.println("The answer of the recursive sum is: " + recursivesum(n,m));
    System.out.println("The answer of the iterative sum is: " + iterativesum(n,m));
}
 }

public static int recursivesum（int n，int m）{
if（nrecursivesum（int n，int m）

方法中的（int i=n；i），您已经在if条件中声明了

s

，但是，您尝试在其他部分访问它

public static int recursivesum(int n, int m){
    int s = n; // Now s having method local scope

    if (n < m){
        s += recursivesum(n+2, m);

    } else{
        if(m < n){
            int  s = m;
            s += recursivesum(m+2, n);

        }
    }
    return s;
}

public static int recursivesum（int n，int m）{
int s=n；//现在s具有方法局部作用域
if（n

在

递归求和（int n，int m）

函数中，

变量s

的范围在

if and else

块内。当您返回

s

时，它超出范围

尝试使用一些IDE，如eclipse。这样您可以立即调试这些错误

int s;
if (n < m){
        s = n;
        s += recursivesum(n+2, m);

    } else{
        if(m < n){
            int  s = m;
            s += recursivesum(m+2, n);

        }
    }
    return s;

ints；
if（n

您在

if

语句内部声明变量

s

，这就是为什么会出现这样的错误。从声明

int s

语句外部

if

开始。

此方法就是问题所在：

public static int recursivesum(int n, int m) {
    if (n < m) {
        int s = n; // Variable declared here... scoped to the if
        s += recursivesum(n+2, m);

    } else {
        if (m < n) {
            int  s = m; // Variable declared here... scoped to this if
            s += recursivesum(m+2, n);
        }
    }
    return s; // No such variable in scope!
}

---

请注意，您在

iterativesum

中遇到了相同的问题-编译器此时应该向您抱怨并非所有路径都返回值。您希望

iterativesum（3，3）

做什么？

您的

s

超出了

recursivesum（int n，int m）的范围

method

在

if-else

块之外声明

s

这是范围问题。在if语句中声明变量s，它是变量的（局部定义）

您需要修改这两种方法，如下所示：

递归方法将是

public static int recursivesum(int n, int m) {
    int s = 0;
    if (n < m) {
        s = n;
        s += recursivesum(n + 2, m);
    } else {
        if(m < n){
            s = m;
            s += recursivesum(m + 2, n);
        }
    }
    return s;
}

public static int recursivesum（int n，int m）{
int s=0；
if（n

迭代方法为：

public static int iterativesum(int n, int m) {
    int s = 0;
    if(n < m) {
        s = n;
        for(int i = n; i <= m; i += 2) {
            s += i;
        }
    } else {
        if(m < n) {
            s = m;
            for(int i = m; i <= n; i += 2) {
                s += i;
            }
        }
     }
     return s;
}

publicstaticintiterativesum（intn，intm）{
int s=0；
if（n对于（int i=n；i，在第一个方法中定义
s
时，在返回它的范围之外有一个错误。在第二个方法中，在循环内部返回

正如本线程中的其他人所建议的，使用像Eclipse（）或IntelliJ（）这样的IDE

import java.util.Scanner；
公共类分配Q7{
公共静态int递归和（int n，int m）{
int s=n；
if（n对于（int i=n；i您的代码必须是这样的，您不必为循环使用两个

import java.util.Scanner;

public class AssignmentQ7 {

    public static int recursivesum(final int n, final int m) {

        final int lower = n < m ? n : m;
        final int upper = n > m ? n : m;
        final int total = lower;

        if (lower >= upper) {
            return total;
        }
        return total + AssignmentQ7.recursivesum(lower + 2, upper);
    }

    public static int iterativesum(final int n, final int m) {

        final int lower = n < m ? n : m;
        final int upper = n > m ? n : m;

        int total = 0;
        for (int num = lower; num <= upper; num = num + 2) {
            total += num;
        }

        return total;
    }

    public static void main(final String args[]) {

        int n, m;

        final Scanner in = new Scanner(System.in);

        System.out.println("Enter two numbers: ");
        n = in.nextInt();
        m = in.nextInt();

        while (n % 2 == 0) {
            System.out.println("Enter the first number again: ");
            n = in.nextInt();
        }

        while (m % 2 == 0) {
            System.out.println("Enter the second number again: ");
            m = in.nextInt();
        }

        System.out.println("The answer of the recursive sum is: " + AssignmentQ7.recursivesum(n, m));
        System.out.println("The answer of the iterative sum is: " + AssignmentQ7.iterativesum(n, m));
    }
}

import java.util.Scanner；
公共类分配Q7{
公共静态整数递归和（final int n，final int m）{
最终整数下限=nm？n:m；
最终整数总计=较低；
如果（下部>=上部）{
返回总数；
}
返回总计+赋值Q7.递归求和（下+2，上）；
}
公共静态整数迭代和（final int n，final int m）{
最终整数下限=nm？n:m；
int-total=0；
对于（int num=lower；s的num范围在大括号中…在类外部定义它variable@VinayVeluri：不必是类变量。请在if之外声明s变量condition@JonSkeettrue！！返回前作用域未结束的任何变量。
public static int iterativesum(int n, int m) {
    int s = 0;
    if(n < m) {
        s = n;
        for(int i = n; i <= m; i += 2) {
            s += i;
        }
    } else {
        if(m < n) {
            s = m;
            for(int i = m; i <= n; i += 2) {
                s += i;
            }
        }
     }
     return s;
}

import java.util.Scanner;

public class AssignmentQ7  {

  public static int recursivesum(int n, int m) {
    int s = n;
    if (n < m) {
      s += recursivesum(n + 2, m);
    }
    else {
      if (m < n) {
        s = m;
        s += recursivesum(m + 2, n);
      }
    }
    return s;
  }

  public static int iterativesum(int n, int m) {
    int s = 0;
    if (n < m) {
      for (int i = n; i <= m; i += 2) {
        s += i;
      }
    }
    else if (m < n) {
      for (int i = m; i <= n; i += 2) {
        s += i;
      }
    }
    return s;
  }

  public static void main(String args[]) {

    int n, m;

    Scanner in = new Scanner(System.in);

    System.out.println("Enter two numbers: ");
    n = in.nextInt();
    m = in.nextInt();

    while (n % 2 == 0) {
      System.out.println("Enter the first number again: ");
      n = in.nextInt();
    }

    while (m % 2 == 0) {
      System.out.println("Enter the second number again: ");
      m = in.nextInt();
    }

    System.out.println("The answer of the recursive sum is: " + recursivesum(n, m));
    System.out.println("The answer of the iterative sum is: " + iterativesum(n, m));
  }
}

import java.util.Scanner;

public class AssignmentQ7 {

    public static int recursivesum(final int n, final int m) {

        final int lower = n < m ? n : m;
        final int upper = n > m ? n : m;
        final int total = lower;

        if (lower >= upper) {
            return total;
        }
        return total + AssignmentQ7.recursivesum(lower + 2, upper);
    }

    public static int iterativesum(final int n, final int m) {

        final int lower = n < m ? n : m;
        final int upper = n > m ? n : m;

        int total = 0;
        for (int num = lower; num <= upper; num = num + 2) {
            total += num;
        }

        return total;
    }

    public static void main(final String args[]) {

        int n, m;

        final Scanner in = new Scanner(System.in);

        System.out.println("Enter two numbers: ");
        n = in.nextInt();
        m = in.nextInt();

        while (n % 2 == 0) {
            System.out.println("Enter the first number again: ");
            n = in.nextInt();
        }

        while (m % 2 == 0) {
            System.out.println("Enter the second number again: ");
            m = in.nextInt();
        }

        System.out.println("The answer of the recursive sum is: " + AssignmentQ7.recursivesum(n, m));
        System.out.println("The answer of the iterative sum is: " + AssignmentQ7.iterativesum(n, m));
    }
}