Passing a two-dimensional array through multiple methods [closed]

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I'm having a bit of trouble with a program I am writing for school. Essentially, I have to use multiple methods and pass a two-dimensional array through them. To do that I have to use nested for loops in the methods, but the methods are not letting me return the "total". You can see the methods I am using below. The bottom two methods are working fine, just the ones with the total variables are not. (Yes, I have tried using other names.)

//method sum of each row
public static int rowsum(int [][] matrix){
    System.out.println("Row Totals***************************************");
    for (int row = 0; row<matrix.length; row++){
        int total = 0;
        for (int column = 0; column<matrix.length; column++)
            total += matrix[row][column];
        System.out.println("The sum of row "+row+" is: "+total);
    }
    return total; 
}
//method sum of each column
public static int columnsum(int[][] matrix){
    System.out.println("Column Totals************************************");
    for (int column = 0; column<matrix[0].length; column++){
        int total = 0;
        for (int row = 0; row<matrix.length; row++){
            total += matrix[row][column];
        System.out.println("The sum of column "+column+" is: "+total);
        }
    return total;
    }
return total;
}
//method product if rows
public static int rowprod(int [][] matrix){
    System.out.println("Row Product**************************************");
    for (int row = 0; row<matrix.length; row++){
        int total = 0;
        for (int column = 0; column<matrix.length; column++)
            total *= matrix[row][column];
        System.out.println("The sum of column "+row+" is: "+total);
    }
return total;
}    
//method product of columns
public static int columnprod(int [][] matrix){
    System.out.println("Column Product***********************************");
    for (int column = 0; column<matrix[0].length; column++){
        int total = 0;
        for (int row = 0; row<matrix.length; row++)
            total = total*matrix[row][column];
        System.out.println("The sum of column "+column+" is: "+total);
    }
    return total;
}
//method highest value in matrix
public static int highest(int [][] matrix){
   System.out.println("This greatest value in this matrix is: ");
   int high = matrix [0][0];
   for (int row = 0; row<matrix.length;row++){
       for(int column=0;column<matrix.length; column++){
           if(high<matrix[row][column]){
               high=matrix[row][column];
           }
       }
   }
   return  high;
}
//method lowest value of matrix
public static int lowest(int [][] matrix){
   System.out.println("The lowest value in this matrix is: ");
   int low = matrix [0][0];
   for (int row = 0; row<matrix.length;row++){
       for(int column=0;column<matrix.length; column++){
           if(low>matrix[row][column]){
               low=matrix[row][column];
           }
       }
   }
   return low;
}

The total variables are only visible inside the for-loops. Define them outside the loops. — sinclair
– sinclair, Commented Oct 29, 2017 at 14:24
Possible duplicate of Scope of variable declared inside a for loop — sinclair
– sinclair, Commented Oct 29, 2017 at 14:26

noob10293 · Accepted Answer · 2022-12-15 10:16:48Z

The issue is with the variable scopes, Your code is flawed in these places

public static int columnsum(int[][] matrix){
System.out.println("Column Totals************************************");
for (int column = 0; column<matrix[0].length; column++){
    int total = 0; // total is defined within the for loop you cannot access it outside the for loop
    for (int row = 0; row<matrix.length; row++){
        total += matrix[row][column];
    System.out.println("The sum of column "+column+" is: "+total);
    }
return total; // Java does not know the total variable since it's already got destroyed after the for loop got terminated
}

How to correct this ??

public static int columnsum(int[][] matrix){
System.out.println("Column Totals************************************");
int total = 0; // define total here
for (int column = 0; column<matrix[0].length; column++){
    
    for (int row = 0; row<matrix.length; row++){
        total += matrix[row][column];
    System.out.println("The sum of column "+column+" is: "+total);
    }
return total;
}

DO this in all cases where total malfunctions

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