Example: Array Insertion in C in C

// Array Insertion in C
#include <stdio.h>

#define MAX_SIZE 10 // Define a maximum physical size for the array

// Function to print the array
void printArray(int arr[], int size) {
    int i;
    for (i = 0; i < size; i++) {
        printf("%d ", arr[i]);
    }
    printf("\n");
}

// Function to insert an element at a specific position
// Returns 1 on success, 0 on failure (e.g., array full or invalid position)
int insertElement(int arr[], int *currentSize, int element, int position) {
    // Step 1: Check if the array is full
    if (*currentSize >= MAX_SIZE) {
        printf("Error: Array is full. Cannot insert.\n");
        return 0;
    }

    // Step 2: Check for valid insertion position
    // Position must be between 0 and currentSize (inclusive)
    if (position < 0 || position > *currentSize) {
        printf("Error: Invalid position for insertion.\n");
        return 0;
    }

    // Step 3: Shift elements to the right to make space
    // Start from the last element and move towards the insertion point
    for (int i = *currentSize - 1; i >= position; i--) {
        arr[i + 1] = arr[i];
    }

    // Step 4: Insert the new element
    arr[position] = element;

    // Step 5: Increment the current size of the array
    (*currentSize)++;

    return 1; // Success
}

int main() {
    int arr[MAX_SIZE] = {10, 20, 30, 40, 50}; // Initial elements
    int currentSize = 5; // Current number of elements in the array

    printf("Original array: ");
    printArray(arr, currentSize);

    // Insert 25 at position 2
    printf("Attempting to insert 25 at position 2...\n");
    if (insertElement(arr, &currentSize, 25, 2)) {
        printf("Array after insertion: ");
        printArray(arr, currentSize);
    }

    // Insert 5 at position 0
    printf("Attempting to insert 5 at position 0...\n");
    if (insertElement(arr, &currentSize, 5, 0)) {
        printf("Array after insertion: ");
        printArray(arr, currentSize);
    }

    // Try to insert beyond max size (demonstrates error handling)
    printf("Attempting to insert 99 at an invalid position (large index)...\n");
    insertElement(arr, &currentSize, 99, 15);

    printf("Attempting to insert 60 at position 8 (array full scenario later)...\n");
    if (insertElement(arr, &currentSize, 60, currentSize)) {
        printf("Array after insertion: ");
        printArray(arr, currentSize);
    }
    printf("Current size after multiple insertions: %d\n", currentSize);

    return 0;
}