CODEWITHSUNDEEP
javaarrays
user3288334
user3288334

Reputation: 7

using an array and array lists

My project is to create a program that does this:

The array of type double called grades has been initialized with the test scores for a class. The course instructor would like the highest score, the lowest score, and the mean value of all the grades.

I'm getting the following errors when I compile the following code:

File: C:\Users\Guest\Downloads\grades.java [line: 16]
Error: Type mismatch: cannot convert from double to int
File: C:\Users\Guest\Downloads\grades.java [line: 23]
Error: grades cannot be resolved to a variable
File: C:\Users\Guest\Downloads\grades.java [line: 23]
Error: Type mismatch: cannot convert from double to int

 import java.util.Scanner;

public class grades
{
 // global variable declaration
 static Scanner cin = new Scanner(System.in);
 static final double NUM_GRADES = 5;

 public static void main(String[] args)
 {
      // declare variables
      double highestGrade = -999999;
      double lowestGrade = 999999;
      double sumOfGrades = 0;
      double avgGrades = 0;
      double[] scores = new double[NUM_GRADES]; // array is initialized using a final variable

      // use a for loop to obtain data from  user using the final variable
      for(double index=0; index < NUM_GRADES; ++index)
      {

          // this puts data into the current array index
           grades[index] = cin.nextDouble();

           // this calculates a running total of all the scores
           sumOfGrades += grades[index];

           // if current score in the array index is bigger than the current 'highestScore'
           // value, then set 'highestScore' equal to the current value in the array
           if(grades[index] > highestGrade)
           {
                highestGrade = grade[index];
           }

           // if current score in the array index is smaller than the current 'lowestScore'
           // value, then set 'lowestScore' equal to the current value in the array
           if(lowestGrade > grades[index])
           {
                lowestGrade = grades[index];
           }               
      }

      {
           System.out.print("\nThe grade for student #"+(index+1)+" is: "+grades[index]);
      }

      // display the highest/lowest numbers to the screen
      System.out.print("\n\nThese are the highest and lowest grades: ");
      System.out.print("\n\tHighest: "+ highestGrade);
      System.out.print("\n\tLowest: "+ lowestGrade);

 // find the average
 avgScores = sumOfGrades/NUM_GRADES;
 System.out.print("\nThe average score is: "+ avgGrades);

 // reset data back to 0 so we can find the ommitted average
 sumOfGrades = 0;
 avgGrades = 0;

}
}

Upvotes: 0

Views: 166

Answers (6)

Mukus
Mukus

Reputation: 5033

To fix compile time errors. 

import java.util.Scanner;

public class Grade //changed here
{
 // global variable declaration
 static Scanner cin = new Scanner(System.in);
 static final int NUM_GRADES = 5;//changed here

 public static void main(String[] args)
 {
  // declare variables
  double highestGrade = -999999;
  double lowestGrade = 999999;
  double sumOfGrades = 0;
  double avgGrades = 0;
  double[] scores = new double[NUM_GRADES]; // array is initialized using a final variable

  // use a for loop to obtain data from  user using the final variable
  for(int index=0; index < NUM_GRADES; ++index)//changed here
  {

      // this puts data into the current array index
       //changed here
       scores[index] = cin.nextDouble();

       // this calculates a running total of all the scores
       sumOfGrades += scores[index];//changed here

       // if current score in the array index is bigger than the current 'highestScore'
       // value, then set 'highestScore' equal to the current value in the array
       if(scores[index] > highestGrade) //changed here
       {
            highestGrade = scores[index]; //changed here
       }

       // if current score in the array index is smaller than the current 'lowestScore'
       // value, then set 'lowestScore' equal to the current value in the array
       if(lowestGrade > scores[index])
       {
            lowestGrade = scores[index];//changed here
       }               
  }

  {
       System.out.print("\nThe grade for student #"+(index+1)+" is: "+scores[index]);//changed here
  }

  // display the highest/lowest numbers to the screen
  System.out.print("\n\nThese are the highest and lowest grades: ");
  System.out.print("\n\tHighest: "+ highestGrade);
  System.out.print("\n\tLowest: "+ lowestGrade);

 // find the average
 avgScores = sumOfGrades/NUM_GRADES;
 System.out.print("\nThe average score is: "+ avgGrades);

 // reset data back to 0 so we can find the ommitted average
 sumOfGrades = 0;
 avgGrades = 0;

}
}

Upvotes: 0

Melquiades
Melquiades

Reputation: 8598

  • Error: Type mismatch: cannot convert from double to int - you are initializing an array using double as the size, which is not allowed, change NUM_GRADES type to int:

    static final int NUM_GRADES = 5;

  • Error: grades cannot be resolved to a variable - you don't have a variable called grades, that's why the compiler is complaining; probably your variable scores should be called grades

  • Error: Type mismatch: cannot convert from double to int - you are using double to index an array in for loop, change it to int:

    for (int index = 0; index < NUM_GRADES; ++index)

EDIT (few more):

  • variable grade doesn't exist in this piece of code:

    if(grades[index] > highestGrade)
{
    highestGrade = grade[index]; //<------- change it to grades
}

  • your print() statement is outside for loop, so index variable will not be accessible; move it inside the loop

  • avgScores is also not declared as variable, it should probably be avgGrades, which you declared at the beginning

Upvotes: 3

Ted Bigham
Ted Bigham

Reputation: 4348

if(lowestGrade > grades[index])

...

System.out.print("\nThe grade for student #"+(index+1)+" is: "+grades[index]);

'index' would need to be an int (or cast to it) to be an array index.

This should fix you...

for(int index=0; index < NUM_GRADES; ++index)

Upvotes: 0

Rainbolt
Rainbolt

Reputation: 3660

NUM_GRADE is a double. You can't use doubles as an index to an array. Try declaring it as an int instead, like this:

static final int NUM_GRADES = 5;

You made the same mistake with index. Declare it as an int.

grades doesn't exist. You probably meant to use scores.

Upvotes: 0

Kyle
Kyle

Reputation: 4298

For the "cannot convert from double to int" error, you can force a conversion by casting to int e.g. grades[index] = (int)cin.nextDouble(); but this amounts to "chopping off" the decimal places from the double and you end up with an int that is basically "rounded down" if that makes sense.

For the "grades cannot be resolved to a variable" error "grades" has not been declared as a variable whatsoever (like scores was).

Upvotes: 0

rgettman
rgettman

Reputation: 178343

You can only use an int as the size in between brackets [] for an array size. Declare your NUM_GRADES constant to be an int, not a double.

You declared an double array called scores, but you don't use it, and then you refer to grades which doesn't exist. Either change all grades references to scores or change the name of scores to grades.

Upvotes: 4

Related Questions