The following code is meant to find the largest value in a 2-d array. int[][] vals = /* Initialization not Shown */ int m = /* Initialization not Shown */ for (int i = 0; i

Question

The following code is meant to find the largest value in a 2-d array.

int[][] vals = /* Initialization not Shown */
int m = /* Initialization not Shown */

for (int i = 0; i < vals.length; i++)
{
  for (int j = 0; j < vals[i].length; j++)
  {
    if (vals[i][j] > m)
      m = vals[i][j];
  }
}

System.out.println(m);

What should m be set to in order for the code to work as intended?

BlackTom AI · Accepted Answer

m should be set to Integer.MIN_VALUE because the algorithm updates m only when it finds a value greater than the current m; to guarantee the largest array element replaces m even when all elements are negative, m must start lower than any possible int in the array.

Relevant concepts:
- The code scans every element and assigns m = vals[i][j] only when vals[i][j] > m, so m acts as a running maximum.
- If m starts too large, no element will be greater and m will remain incorrect; if it starts too high (e.g., Integer.MAX_VALUE) it will never change. If it starts at 0, negative-only arrays will give wrong results.
- Java provides Integer.MIN_VALUE as the smallest possible int constant: -2^31 = -2,147,483,648, which is guaranteed to be ≤ every int in the array.

Step-by-step reasoning:
1. Initialize m = Integer.MIN_VALUE.
2. For each i and j, compare vals[i][j] to m.
3. If vals[i][j] > m, assign m = vals[i][j].
4. After checking all elements, m holds the largest value encountered.

Illustrative example:
- Suppose vals contains [-3, -7, -1]. If m = 0, comparisons yield -3 > 0? No; -7 > 0? No; -1 > 0? No → m remains 0 (incorrect). If m = Integer.MIN_VALUE (-2,147,483,648), first element -3 > m → m becomes -3; then -7 > -3? No; -1 > -3? Yes → m becomes -1 (correct largest).

Why other initializations are wrong:
- m = 0 fails when all values are negative.
- m = Integer.MAX_VALUE (2,147,483,647) will never be replaced unless an element exceeds that (impossible for int), so result stays wrong.
- m = vals[0][0] would work only if the array and first row exist and you explicitly handle empty arrays; question doesn’t show such initialization.

Therefore the correct choice is Integer.MIN_VALUE, matching the provided answer.

类似问题

Which statement declares a two-dimensional integer array called myArray with 3 rows and 4 columns?

What is the output of the following code: int arr[4][4] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}; for (int j = 2; j < 3; j++) for(int i = 0; i < 4; i++) cout << arr[i][j];

Consider the following code segment. int[][] mat = new int[4][6]; for (int r = 0; r < 4; r++) { for (int c = 0; c < 6; c++) { if(c < 3 - r || c > 3 + r) { mat[r][c] = 0; } else { mat[r][c] = 1; } } } Which of the following represents mat after this code segment is executed?

Consider the following method intended to swap the first and second rows in a two-dimensional array: public static void swapRow(int[][] a) { /* missing code / } Which of the following correctly replaces / missing code */?

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单