Question

Is there a problem with the following code segment? If not, in detail, What are the consequences?

int nums[10];
nums[10] = 100;

Answer 1

The code attempts to write to the 11th element of an array that only has 10 elements, causing an array index out of bounds error, a form of buffer overflow, which can lead to undefined behavior and potential program crashes or data corruption.

Step-by-step explanation:

The code segment in question does have a problem. Specifically, it attempts to assign a value to the 11th element of an array that only has space for 10 elements.

Arrays in C and C++ are zero-indexed, which means that the index of the first element is 0, and the index of the last element is one less than the size of the array. Therefore, for an array declared as int nums[10];, valid indices are 0 through 9. When you try to use nums[10] = 100;, this is writing to memory that is not allocated for the nums array, which can lead to undefined behavior, potentially causing a crash or corrupting data.

The consequence of such an action is typically a runtime error, specifically, an array index out of bounds error. It's a common mistake known as a buffer overflow, which can introduce serious vulnerabilities in software applications.