How to avoid array out of bounds?

To avoid array out-of-bounds, you can perform a range or bounds check or use a sentinel value before accessing an element. Range checks verify that the index is within a valid range, bounds checks simply verify that the index is below the array size, and sentinels add an extra "sentinel" element to the bounds of the array.

How to avoid array out-of-bounds

Array out-of-bounds refers to accessing an element beyond the valid range of the array. This can lead to undefined behavior, including program crashes or incorrect results. Here are some techniques to avoid array out-of-bounds techniques:

1. Range Check

Before accessing an array element, check whether the index is within a valid range. For example, the following C++ code checks if the index is greater than or equal to 0 and less than the array size:

int array[] = {1, 2, 3};
int index = 2;

if (index >= 0 && index < sizeof(array) / sizeof(array[0])) {
  // 安全地访问元素
} else {
  // 处理越界情况
}

2. Bounds check

Simply checks if the index is less than the array size. For example:

int[] array = {1, 2, 3};
int index = 2;

if (index < array.length) {
  // 安全地访问元素
} else {
  // 处理越界情况
}

3. Initialize an array with an index of bounds

, one element larger than actually required, giving it a "sentinel" value. For example:

array = [0] * (size + 1)

Then, place the sentinel value in the last element and check its index before accessing the element:

if index < size:
  # 安全地访问元素
else:
  # 处理越界情况

Practical example:

Consider a program that needs to read an array of numbers entered by the user. To avoid crossing the line, you can use the following C# code:

Console.WriteLine("Enter the size of the array:");
int size = int.Parse(Console.ReadLine());

int[] array = new int[size];

for (int i = 0; i < array.Length; i++)
{
    Console.WriteLine($"Enter the value for index {i}:");
    array[i] = int.Parse(Console.ReadLine());
}

Console.WriteLine("The values in the array:");
for (int i = 0; i < array.Length; i++)
{
    Console.WriteLine($"{i}: {array[i]}");
}

The above is the detailed content of How to avoid array out of bounds?. For more information, please follow other related articles on the PHP Chinese website!