Array Deletion at End in DSA C - Execution Trace

Concept Flow - Array Deletion at End

Start with array

↓

Check if array is empty?

Yes→Stop: Nothing to delete

No↓

Remove last element

↓

Update array size

↓

Done

This flow shows checking if the array is empty, then removing the last element and updating the size.

Execution Sample

DSA C

int arr[5] = {10, 20, 30, 40, 50};
int size = 5;
// Delete last element
if (size > 0) {
  size--;
}

This code deletes the last element by reducing the size count if the array is not empty.

Execution Table

Step	Operation	Array Size	Pointer Changes	Visual State
1	Start with array	5	head -> arr[0]	[10, 20, 30, 40, 50]
2	Check if array is empty (size=5)	5	head -> arr[0]	[10, 20, 30, 40, 50]
3	Delete last element (size--)	4	head -> arr[0]	[10, 20, 30, 40, 50]
4	Done	4	head -> arr[0]	[10, 20, 30, 40, 50]

💡 Array size reduced from 5 to 4, last element logically removed

Variable Tracker

Variable	Start	After Step 3	Final
size	5	4	4
arr	[10, 20, 30, 40, 50]	[10, 20, 30, 40, 50]	[10, 20, 30, 40, 50]

Key Moments - 2 Insights

Why does the array still show the last element after deletion?

The execution_table row 3 shows size reduces to 4 but the array data remains unchanged. The last element is logically removed by ignoring it via size, not physically erased.

What happens if we try to delete when the array is empty?

Step 2 checks if size > 0. If size is 0, deletion stops immediately to avoid errors, as shown in the concept_flow.

Visual Quiz - 3 Questions

Look at the execution_table at Step 3, what is the array size?

A 4

B 5

C 3

D 0

💡 Hint

Check the 'Array Size' column at Step 3 in execution_table

At which step does the array size change?

A Step 1

B Step 2

C Step 3

D Step 4

💡 Hint

Look for 'Delete last element' operation in execution_table

If size was 0 at Step 2, what would happen next?

A Delete last element and reduce size

B Stop deletion, no change

C Array size becomes negative

D Array elements shift left

💡 Hint

Refer to concept_flow decision at 'Check if array is empty?'

Concept Snapshot

Array Deletion at End:
- Check if array size > 0
- Reduce size by 1 to delete last element
- Data remains but ignored beyond size
- No physical element removal
- Prevent deletion if empty

Full Transcript

We start with an array of size 5 containing elements 10, 20, 30, 40, 50. First, we check if the array is empty by verifying if size is greater than zero. Since size is 5, we proceed to delete the last element by reducing the size to 4. The array data remains unchanged, but logically the last element is removed by ignoring it beyond the new size. If the array was empty (size 0), deletion would stop immediately to avoid errors. This method efficiently deletes the last element by adjusting size without shifting or erasing data.