Question

How to sum 2D array (matrix) cols in Java

Answer 1

public class MyClass {
    public static void main(String args[]) {
        int[][] matrix = {{31, 22, 33}, 
                          {42, 85, 987}};
        int[] cols_sum = {0, 0, 0};
         
        sum_matrix_cols(matrix, cols_sum);
         
        for (int i = 0; i < 3; i++) 
            System.out.println(cols_sum[i]);
    }
    public static void sum_matrix_cols(int[][] matrix, int[] cols_sum) {
        int rows = matrix.length;
        int cols = matrix[0].length;
           
         for (int j = 0; j < cols; j++) {
                for (int i = 0; i < rows; i++)
                    cols_sum[j] += matrix[i][j];
        }
    }
}
    
/*
                   
run:
      
73
107
1020
          
*/

 

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