Java：二维数组最小值和最大值

Question

I am working on this program to find minium and maximum values of the variable milesTracker and have been successful for a few tests but it breaks testing it with values {{-5}, {-93}, {-259}}.

Note: I cannot edit anything outside of the commented area, however, I can add more lines anywhere within the commented area.

I'd appreciate the help.

My code:

import java.util.Scanner;

public class ArraysKeyValue {
   public static void main (String [] args) {
      final int NUM_ROWS = 2;
      final int NUM_COLS = 2;
      int [][] milesTracker = new int[NUM_ROWS][NUM_COLS];
      int i = 0;
      int j = 0;
      int maxMiles = 0; // Assign with first element in milesTracker before loop
      int minMiles = 0; // Assign with first element in milesTracker before loop

      milesTracker[0][0] = -10;
      milesTracker[0][1] = 20;
      milesTracker[1][0] = 30;
      milesTracker[1][1] = 40;

      // Start of area to be modified
      for(i=0;i<NUM_ROWS;++i){
         for(j=0;j<NUM_COLS;++j){
             if (milesTracker[i][j]<minMiles){
               minMiles = milesTracker[i][j];
            }
             else if (milesTracker[i][j] > maxMiles){
               maxMiles = milesTracker[i][j];
            }
         } 
      }
      // End of area to be modified

      System.out.println("Min miles: " + minMiles);
      System.out.println("Max miles: " + maxMiles);
   }
}

Errors:

Answer 1

// Start of area to be modified
maxMiles = milesTracker[0][0];
minMiles = milesTracker[0][0];

for(i=0; i < NUM_ROWS; i++){
    for(j=0; j < NUM_COLS; j++){
        if (milesTracker[i][j] < minMiles){
            minMiles = milesTracker[i][j];
        }
        else if (milesTracker[i][j] > maxMiles){
            maxMiles = milesTracker[i][j];
        }
    } 
}

Answer 2

You initialize,

int maxMiles = 0;

Yet you only update maxMiles ,

if(milesTracker[i][j] > maxMiles)

while iterating through your array with {{-5},{-93},{-253}} , none of those values are greater than maxMiles == 0 . Thus maxMiles is never updated.

Try declaring it arbitrarily within the set

int maxMiles = milesTracker[0][0];

Then maxMiles cannot be out of the set.