Array Operations

Master insertion, deletion, searching, and traversal with interactive examples

Interactive Array Operations

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Array size: 5 | Last operation: None

Insert

Delete

Search

Core Array Operations

Pseudocode

1ALGORITHM: Array Insert at Index
2INPUT: array[], size, index, value
3OUTPUT: modified array[] with increased size
4 
5BEGIN
61. IF index < 0 OR index > size THEN
72.     RETURN "Invalid Index"
83. END IF
94. 
105. FOR i = size DOWN TO index + 1 DO
116.     array[i] = array[i-1]     // Shift elements right
127. END FOR
138. 
149. array[index] = value          // Insert new value
1510. size = size + 1              // Increase array size
1611. RETURN "Success"
17END

C++ Implementation:

// Insert operation in C++
void insertAt(int arr[], int &size, int index, int value) {
    // Shift elements to the right
    for(int i = size; i > index; i--) {
        arr[i] = arr[i-1];
    }
    arr[index] = value;
    size++;
}

Time Complexity Analysis

Access by Index

Direct memory access using base + (index × element_size)

O(1)

Linear Search

Must check each element until found or end reached

O(n)

Insert at Beginning

Must shift all existing elements to the right

O(n)

Insert at End

Direct insertion if space available (*amortized for dynamic arrays)

O(1)*

Delete from Beginning

Must shift all remaining elements to the left

O(n)

Delete from End

Simply reduce the size, no shifting required

O(1)

Common Pitfalls & Best Practices

❌ Common Mistakes

Buffer Overflow: Inserting beyond array bounds
```
arr[1000] = value; // If array size is 100
```

Off-by-One Errors: Incorrect loop bounds

for(i = 0; i <= size; i++) // Should be i < size

Not Updating Size: Forgetting to modify array size after operations

✅ Best Practices

Bounds Checking: Always validate indices before access
```
if(index >= 0 && index < size) 
```
Use const for read-only: Prevent accidental modifications
```
void print(const int arr[], int size)
```
Consider std::vector: For dynamic sizing and safety

Previous: Memory Layout Next: Array Algorithms

Core Array Operations

Pseudocode

1ALGORITHM: Array Insert at Index
2INPUT: array[], size, index, value
3OUTPUT: modified array[] with increased size
4 
5BEGIN
61. IF index < 0 OR index > size THEN
72.     RETURN "Invalid Index"
83. END IF
94. 
105. FOR i = size DOWN TO index + 1 DO
116.     array[i] = array[i-1]     // Shift elements right
127. END FOR
138. 
149. array[index] = value          // Insert new value
1510. size = size + 1              // Increase array size
1611. RETURN "Success"
17END

C++ Implementation:

// Insert operation in C++
void insertAt(int arr[], int &size, int index, int value) {
    // Shift elements to the right
    for(int i = size; i > index; i--) {
        arr[i] = arr[i-1];
    }
    arr[index] = value;
    size++;
}

Common Pitfalls & Best Practices

❌ Common Mistakes

Buffer Overflow: Inserting beyond array bounds
```
arr[1000] = value; // If array size is 100
```

Off-by-One Errors: Incorrect loop bounds

for(i = 0; i <= size; i++) // Should be i < size

Not Updating Size: Forgetting to modify array size after operations

✅ Best Practices

Bounds Checking: Always validate indices before access
```
if(index >= 0 && index < size) 
```
Use const for read-only: Prevent accidental modifications
```
void print(const int arr[], int size)
```
Consider std::vector: For dynamic sizing and safety