In this article, we will write a C program that calculates the sum and average of an array.

The program first asks the user to enter the size of the array and then takes the array elements as input. The sum and average of the array elements is printed on the screen.

**Sample Input:**

```
Enter the size of the array: 5
Enter the array elements: 1 2 3 4 5
```

**Sample Output:**

```
Sum of array elements is: 15
Avg. of arrays elements is: 3.00
```

To calculate the sum and average of an array, we can initialize a variable `sum`

to 0 and then use a for or a while loop to iterate through the given array and add each element of the array to the `sum`

variable.

Then to calculate the average of the array, we can divide the calculated sum by the size of the array.

See the following implementation:

// C program to calculate the sum // and avg. of array elements #include <stdio.h> int main(){ int arr[100], size, sum; float avg; printf("Enter the size of the array: "); scanf("%d", &size); printf("Enter the array elements: "); for(int i = 0; i < size; i++){ scanf("%d", &arr[i]); } // Set the initial sum to zero sum = 0; // Loop through the array to calculate the sum for(int i = 0; i < size; i++){ sum = sum + arr[i]; } // Calculate the avg avg = sum / size; printf("Sum of array elements is: %d", sum); printf("\nAvg. of arrays elements is: %.2f", avg); return 0; }

**Output:**

Enter the size of the array: 5 Enter the array elements: 1 2 3 4 5 Sum of array elements is: 15 Avg. of arrays elements is: 3.00

### Code Explanation:

- The program defines an integer array
`arr`

with a maximum size of 100. - The program also defines an integer variable
`size`

to store the size of the array, a variable`sum`

to store the sum of the elements, and a variable`avg`

to store the average of the elements. - Prompts the user to enter the size of the array using
`printf()`

function and reads the input using`scanf()`

function. - Initializes the
`sum`

variable to 0. - Calculates the sum of the elements by iterating through each element of the array using the for loop and adding the value of each element to the
`sum`

variable. - Calculates the average of the elements by dividing the
`sum`

variable by the`size`

variable and assigning the result to the`avg`

variable. - Prints the sum of the elements using
`printf`

and the`%d`

format specifier. - The program also prints the average of the elements using
`printf`

and the`%f`

format specifier with a precision of two decimal places using`.2`

before the`f`

specifier.

That’s all for this article. Thanks for reading!