Array Average

// Method 1: Using for loop
function averageLoop(arr) {
    if (arr.length === 0) return 0;
    
    let sum = 0;
    for (let i = 0; i < arr.length; i++) {
        sum += arr[i];
    }
    return sum / arr.length;
}

let numbers = [10, 20, 30, 40, 50];
console.log("Array:", numbers);
console.log("Average:", averageLoop(numbers));

// Method 2: Using reduce
function averageReduce(arr) {
    if (arr.length === 0) return 0;
    
    let sum = arr.reduce((acc, num) => acc + num, 0);
    return sum / arr.length;
}

console.log("\nUsing reduce:", averageReduce([5, 10, 15, 20]));

// Method 3: Using forEach
function averageForEach(arr) {
    if (arr.length === 0) return 0;
    
    let sum = 0;
    arr.forEach(num => sum += num);
    return sum / arr.length;
}

console.log("\nUsing forEach:", averageForEach([2, 4, 6, 8, 10]));

// Method 4: One-liner with reduce
const average = arr => arr.length ? arr.reduce((a, b) => a + b) / arr.length : 0;

console.log("\nOne-liner:", average([1, 2, 3, 4, 5]));

// Method 5: With precision
function averagePrecise(arr, decimals = 2) {
    if (arr.length === 0) return 0;
    let avg = arr.reduce((a, b) => a + b) / arr.length;
    return parseFloat(avg.toFixed(decimals));
}

console.log("\nWith precision:", averagePrecise([1, 2, 3], 2));

Array: [ 10, 20, 30, 40, 50 ]
Average: 30

Using reduce: 12.5

Using forEach: 6

One-liner: 3

With precision: 2

This program demonstrates different methods to calculate the average of array elements.

Average Formula

Average = Sum of all elements / Number of elements

Method 1: For Loop

Traditional iterative approach:

javascript
let sum = 0;
for (let i = 0; i < arr.length; i++) {
    sum += arr[i];
}
return sum / arr.length;

Method 2: Reduce

Functional approach:

javascript
let sum = arr.reduce((acc, num) => acc + num, 0);
return sum / arr.length;

Reduce Syntax:

javascript
arr.reduce((accumulator, currentValue) => {
    // return new accumulator
}, initialValue);

Method 3: ForEach

Iterate and accumulate:

javascript
let sum = 0;
arr.forEach(num => sum += num);
return sum / arr.length;

ForEach vs For Loop:

• ForEach: Functional, can't break
• For loop: Can break/continue, more control

Method 4: Arrow Function One-Liner

Concise ES6 syntax:

javascript
const average = arr => arr.length ? arr.reduce((a, b) => a + b) / arr.length : 0;

Ternary Operator:

• Checks if array has elements
• Returns 0 if empty (avoid division by zero)

Method 5: With Precision

Control decimal places:

javascript
return parseFloat(avg.toFixed(decimals));

Number Methods:

• toFixed(n): Rounds to n decimals, returns string
• parseFloat(): Converts string to number

Edge Cases:

• Empty array: Return 0 or handle error
• Single element: Returns that element
• Negative numbers: Works normally

When to Use:

• Loop: Learning, simple

• Reduce: Modern, functional

• One-liner: Quick calculations

• Precise: When decimal control needed