Create an array of size 10, input values and display sum and average of all elements in the array.

array_sum_avg.c

#include <stdio.h>

int main() {
    int arr[10], i, sum = 0;  // Step 1: Declare array and variables
    float avg;

    // Step 2: Input elements from user
    printf("Enter 10 integers:\n");
    for(i = 0; i < 10; i++) {
        printf("Element %d: ", i + 1);
        scanf("%d", &arr[i]);
    }

    // Step 3: Calculate sum
    for(i = 0; i < 10; i++) {
        sum += arr[i];
    }

    // Step 4: Calculate average
    avg = sum / 10.0;

    // Step 5: Display results
    printf("\nSum of all elements = %d", sum);
    printf("\nAverage of all elements = %.2f", avg);

    return 0;
}

🧠 Step-by-Step Explanation

🔹 Step 1: Variable Declaration

int arr[10], i, sum = 0;
float avg;

• arr[10] creates an integer array with 10 elements
• sum initialized to 0 to accumulate total
• avg declared as float for precise division
• i will be used as loop counter

🔹 Step 2: Input Array Elements

for(i = 0; i < 10; i++) {
    scanf("%d", &arr[i]);
}

• Loop runs 10 times (i = 0 to 9)
• Prompts user for each element
• Stores input in array using index i
• &arr[i] gets memory address for storage

🔹 Step 3: Calculate Sum

for(i = 0; i < 10; i++) {
    sum += arr[i];
}

• Iterates through each array element
• Adds each element's value to sum
• After loop completes, sum contains total

🔹 Step 4: Calculate Average

avg = sum / 10.0;

• Divides sum by 10.0 (float division)
• Using 10.0 instead of 10 ensures decimal result
• Result stored in avg variable

🔹 Step 5: Display Results

printf("\nSum of all elements = %d", sum);
printf("\nAverage of all elements = %.2f", avg);

• First printf displays integer sum
• Second printf shows average with 2 decimal places
• %.2f format specifier controls decimal precision

🖨️ Sample Output:

Enter 10 integers:
Element 1: 5
Element 2: 10
Element 3: 15
Element 4: 20
Element 5: 25
Element 6: 30
Element 7: 35
Element 8: 40
Element 9: 45
Element 10: 50

Sum of all elements = 275
Average of all elements = 27.50

💡 Key Concepts:

• Array Basics: Fixed-size collection of same-type elements
• Loop Structures: for loops for controlled iteration
• Type Conversion: Importance of 10.0 for float division
• I/O Formatting: Using %.2f for decimal precision
• Memory Management: Array elements stored contiguously