CODEWITHSUNDEEP
javaarraysclassobjectmethods
Paincakes
Paincakes

Reputation: 147

Using Arrays as Method (Java)

I am having problems getting my class to compile. It is giving me errors such as "double cannot be dereferenced" and "cannot find symbol".

The diver is:

 public class MinilabArraysDriver{
    public static void main(String[ ] args){
       //create a 1d array of ints
       int[ ] array1d = { 8, 8, 7, 5, 3 };

       //call mean1d Method to find the mean (note the static call...)
       double theMean = MinilabArrays.mean1d(array1d);

       //print the original array and the mean
       System.out.print("The mean of: { ");
        for (int i=0; i<array1d.length; i++){
              if (i != 0)
                  System.out.print("   ");
             //print first for separation (except before first element)
             System.out.print(array1d[i]);
         }
        System.out.print(" }   is:  " + theMean);
        //------------------------------------------------------------
        System.out.println("\n\n");
        //create a 2d array of doubles
        double[ ][ ] array2d =  {{ 3.4,  5.1,  8.0},
                                 { 5.23,  8.2 },
                                 { 10.7 },
                                 { 2.9 }
                                };
        //call sum2d to get the sum
        double total = MinilabArrays.sum2d(array2d);

        //print the 2D array
        for (int row=0; row<array2d.length; row++){
             System.out.println();
             for (int col=0; col<array2d[row].length; col++)
                  System.out.print(array2d[row][col] + "\t");
            }
        //print the result
        System.out.println("\n\nTotal of 2d array is: " + total);
        System.out.println("\n\n");
       }
}

And here is the class that I am trying to write:

public class MinilabArrays{
  public static double mean1d(int[ ] theMean){
    double total = 0;
    for (int i = 0 ;i < theMean.length ; i++){
            total = total + theMean [ i ];
            total = total / theMean.length;
            return total;
        }
    }

   public static double sum2d(double [ ] theSum){
    double total2, total3, total4 = 0;
    for(int row=0 ; row < theSum.length ; row++){
        for (int col=0 ; col<theSum[row].length ; col++)
            total2 = total2 + theSum[col];
        }
    total3 = total3 + theSum[row];
    total4 = total3 + total2;
    return total4;
   }
}

For "mean1d" I am trying to find the mean or average of the given number, and for "sum2d" I am trying to find the total of the given number.

Sorry if my code is stupid or dumb. I cannot check it if it won't let me compile.

Thank you for helping me!

Upvotes: 0

Views: 105

Answers (3)

Alexander
Alexander

Reputation: 490

The first error comes from this line for (int col=0 ; col<theSum[row].length ; col++). You are using a two-dimensional array theSum[][] but declared a one-dimensional array as method parameter.

The other error comes from the use of row outside of its scope. You declared it inside this for-loop for(int row=0 ; row < theSum.length ; row++) but used it outside of the for-loop.

Upvotes: 1

2787184
2787184

Reputation: 3881

You are calling sum2d method by passing 2D array in parameter and declared this method as a 1D array as parameter.

MinilabArrays.java

public static double sum2d(double[][] theSum) {
    double total2 = 0;
    for (int row = 0; row < theSum.length; row++) {
        for (int col = 0; col < theSum[row].length; col++){
            total2 = total2 + theSum[row][col];
        }
    }
    return total2;
}

Upvotes: 1

Madushan Perera
Madushan Perera

Reputation: 2598

MinilabArrays.sum2d(array2d) requires a double[] not the double[][] here. And also at this point total3 = total3 + theSum[row]; cannot access the variable row outside of the for loop.

Upvotes: 1

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