Else-if声明

时间：2014-10-28 23:52:23

标签： java methods

所以我的代码正在努力告诉我平均成绩是多少，但是，我需要它实际做的是告诉我每个等级本身的成绩是什么，例如用户输入test1 80，I需要它说等级是B等等。这就是我到目前为止所拥有的。我不确定我是否可以将多个变量放入1 if else语句中，或者如果Ill必须有5个不同的if语句。

import java.util.Scanner;           //user input
import java.text.DecimalFormat;     //formats decimal places

/*This program is made to recieve 5 test grade inputs from the
user and then calculate their average and return their grade.
*/
public class Lab
{
   public static void main(String[] args)
   {
      //place holders for test scores
      double test1,test2,test3,test4,test5;

      System.out.println("Enter 5 of your test grades: ");

      //create scanner for user imput
      Scanner keyboard = new Scanner(System.in);
      test1 = keyboard.nextDouble();
      test2 = keyboard.nextDouble();
      test3 = keyboard.nextDouble();
      test4 = keyboard.nextDouble();
      test5 = keyboard.nextDouble();
      keyboard.nextLine();

      //calls method 1
      double average = calcAverage(test1, test2, test3, test4, test5);

      //calls method 2
      getGrade(average);

      //formats how the average will be displayed
      DecimalFormat df = new DecimalFormat("0.00");
      System.out.println("The average is: " + df.format(average));
      System.exit(0);
   }

   /*
   The calcAverage method takes the test inputs from the
   user and divides them by 5 getting the average of all 5.
   */

   public static double calcAverage(double test1, double test2, double test3, double test4, double test5)  
   {
      double average = (test1 + test2 + test3 + test4 + test5) / 5;
      return average;  
   }

   /*
   The getGrade method will take what was produced in the calcAverage method
   and find out where the average falls, thus giving the user his/her grade.
   */

   public static void getGrade(double average)
   {
      if (average>90)  
      {  
         System.out.println("You have an A");  
      }  
      else if (average>=80)  
      {  
         System.out.println("You have a B");  
      }  
      else if (average>=70)  
      {  
         System.out.println("You have a C");  
      }  
      else if (average>=60)  
      {  
         System.out.println("You have a D");  
      }  
      else if (average<60)  
      {  
         System.out.println("You have a F");
      }
   }
}

4 个答案:

答案 0 :(得分：1)

您的getGrade()应该可以返回成绩。像，

public static String getGrade(double average)
{
  if (average>90)  
  {  
    return "A";  
  }  
  else if (average>=80)  
  {  
    return "B";  
  }  
  else if (average>=70)  
  {  
    return "C";  
  }  
  else if (average>=60)  
  {  
    return "D";  
  }  
  else  
  {  
    return "F";
  }
}

然后你将其称为单独测试（或平均值） - 

System.out.printf("You got a %s on test1.", getGrade(test1));

答案 1 :(得分：0)

只需针对各个测试调用getGrade，如下所示，并将getGrade参数名称重命名为score而不是average（这只是为了提高可读性）

import java.util.Scanner;           //user input
import java.text.DecimalFormat;     //formats decimal places

/*This program is made to recieve 5 test grade inputs from the
user and then calculate their average and return their grade.
*/
public class Lab
{
   public static void main(String[] args)
   {
      //place holders for test scores
      double test1,test2,test3,test4,test5;

      System.out.println("Enter 5 of your test grades: ");

      //create scanner for user imput
      Scanner keyboard = new Scanner(System.in);
      test1 = keyboard.nextDouble();
      test2 = keyboard.nextDouble();
      test3 = keyboard.nextDouble();
      test4 = keyboard.nextDouble();
      test5 = keyboard.nextDouble();
      keyboard.nextLine();

      //calls method 1
      double average = calcAverage(test1, test2, test3, test4, test5);

      //calls method 2
      getGrade(average);

      // Gets grade for individual tests
      getGrade(test1);
      getGrade(test2);
      getGrade(test3);
      getGrade(test4);
      getGrade(test5);

      //formats how the average will be displayed
      DecimalFormat df = new DecimalFormat("0.00");
      System.out.println("The average is: " + df.format(average));
      System.exit(0);
   }

   /*
   The calcAverage method takes the test inputs from the
   user and divides them by 5 getting the average of all 5.
   */

   public static double calcAverage(double test1, double test2, double test3, double test4, double test5)  
   {
      double average = (test1 + test2 + test3 + test4 + test5) / 5;
      return average;  
   }

   /*
   The getGrade method will take what was produced in the calcAverage method
   and find out where the average falls, thus giving the user his/her grade.
   */

   public static void getGrade(double score)
   {
      if (average>90)  
      {  
         System.out.println("You have an A");  
      }  
      else if (average>=80)  
      {  
         System.out.println("You have a B");  
      }  
      else if (average>=70)  
      {  
         System.out.println("You have a C");  
      }  
      else if (average>=60)  
      {  
         System.out.println("You have a D");  
      }  
      else if (average<60)  
      {  
         System.out.println("You have a F");
      }
   }
}

答案 2 :(得分：0)

我会将您的测试放入Array：

double[] myTests = {test1, test2, test3, test4, test5};

然后迭代：

for(int i=0; i<myTest.length; i++){
    getGrade(myTests[i]);
}

至于您的getGrade方法，您可能只想为每个年级返回char：A，B，C，等等，然后只有一个System.out.print语句。在这种情况下，我个人的偏好是使用switch-case代替if-else。显然这是学校的工作，所以我不知道你希望用什么教育水平编码

答案 3 :(得分：0)

对于更多OO设计，您可以创建一个Test类并将数据封装在其中：

public class Test
{
    public double Score;

    public String GetGrade()
    {
        if (this.Score > 90)  
        {  
            return "A";  
        }  
        else if (this.Score >= 80)  
        {  
            return "B";  
        }  
        else if (this.Score >=70)  
        {  
            return "C";  
        }  
        else if (this.Score >= 60)  
        {  
            return "D";  
        }  
        else  
        {  
            return "F";
        }
    }
}

我假设您的问题包含接受5个测试分数的说明，因此我们可以使用大小为5的数组（否则您可以创建ArrayList并为每个输入添加它）：

Test[] tests = new Test[5];

不是连续接受5个输入，更好的解决方案可能是在输入每个分数时打印出成绩：

System.out.println("Enter test scores:");

//create scanner for user imput
Scanner keyboard = new Scanner(System.in);
for (int i = 0; i < tests.length; i++)
{
    System.out.printf("Test %d: ", i + 1);
    tests[i].Score = keyboard.nextDouble();
    System.out.printf("Grade is %s", tests[i].GetGrade());
}

您的calcAverage也可以更通用，而不是硬编码5：

public static double calcAverage(Test[] tests)  
{
  double scoreSum;

  for (int i = 0; i < tests.length; i++)
  {
      scoreSum += tests[i].Score;
  }

  return scoreSum / test.length;  
}
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