Functions using Array in C

In C programming, you can use arrays with functions to perform operations on arrays more efficiently and make your code modular. Functions help encapsulate logic, making your code easier to read and maintain.

Passing Arrays to Functions

You can pass arrays as arguments to functions to operate on them within the function. When you pass an array to a function, it's actually passing a pointer to the array's first element, allowing the function to work directly with the array.

#include <stdio.h> // Function to calculate the sum of an array int calculateSum(int arr[], int size) { int sum = 0; for (int i = 0; i < size; i++) { sum += arr[i]; } return sum; } int main() { int numbers[] = {1, 2, 3, 4, 5}; int size = 5; int sum = calculateSum(numbers, size); printf("Sum of elements in the array: %d\n", sum); return 0; }

In this example, the calculateSum function takes an array and its size as parameters, and it returns the sum of the elements in the array.

Modifying Arrays within Functions

Functions can also modify array elements when passed as parameters. Here's an example of a function that squares each element of an array in-place:

#include <stdio.h> // Function to square each element of an array void squareArray(int arr[], int size) { for (int i = 0; i < size; i++) { arr[i] = arr[i] * arr[i]; } } int main() { int numbers[] = {1, 2, 3, 4, 5}; int size = 5; squareArray(numbers, size); printf("Squared elements in the array: "); for (int i = 0; i < size; i++) { printf("%d ", numbers[i]); } printf("\n"); return 0; }

In this example, the squareArray function squares each element of the numbers array, and the modified array is reflected in the main function.

Returning Arrays from Functions (Advanced)

In C, you cannot directly return arrays from functions, but you can return a pointer to an array or dynamically allocate memory within the function to return an array. This is an advanced topic and involves pointers and memory management.

Calculates the sum of the elements in an array

You can also use functions to perform more complex operations on arrays. For example, the following function calculates the sum of the elements in an array:

int sumArray(int array[]) { int sum = 0; for (int i = 0; i < sizeof(array) / sizeof(array[0]); i++) { sum += array[i]; } return sum; }

To use the sumArray() function, you would simply pass the name of the array to the function as an argument. For example, the following code calculates the sum of the elements in the myArray array and prints the result to the console:

int myArray[10] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}; int sum = sumArray(myArray); printf("The sum of the elements in the array is: %d\n", sum);
//Output: The sum of the elements in the array is: 55

Here are some additional benefits of using arrays and functions together in C:

  1. Code reusability: Functions can be reused multiple times, which can save you time and effort when writing code.
  2. Modularity: Functions can be used to break down complex problems into smaller, more manageable pieces. This can make your code easier to read, understand, and maintain.
  3. Efficiency: Functions can be optimized to improve the performance of your code.


Arrays can be passed as parameters to functions by specifying the array's data type followed by empty square brackets in the function prototype. This allows functions to operate on arrays, making code more modular and organized. Additionally, array size should be included as a parameter in the function prototype and passed as an argument when calling the function to ensure proper array manipulation.