Imagine you are building an e-commerce application that needs to calculate the total cost of items in a shopping cart. The prices and quantities of the items are stored in two separate arrays. You need to write a function that takes these two arrays as input and returns the total cost.
The Solution
The calculateTotalCost function is a simple and efficient solution to this problem. Here is the code:
JavaScriptfunction calculateTotalCost(prices, quantities) {
// Initialize total cost to 0
let totalCost = 0;
// Loop through prices and quantities arrays
for (let i = 0; i < prices.length; i++) {
// For each item, multiply the price by the quantity and add to total cost
totalCost += prices[i] * quantities[i];
}
// Return the total cost
return totalCost;
}
How it Works
The function works by iterating through the prices and quantities arrays simultaneously, using a for loop. For each item, it multiplies the price by the quantity and adds the result to the totalCost variable. Finally, it returns the totalCost.

Example Usage
To demonstrate the usage of the calculateTotalCost function, let’s consider an example. Suppose we have the following prices and quantities:
JavaScriptconst prices = [10, 20, 30];
const quantities = [2, 3, 1];
We can call the calculateTotalCost function with these arrays as arguments:
JavaScriptconsole.log(calculateTotalCost(prices, quantities)); // Output: 110
The output will be 110, which is the total cost of the items.
Advantages
The calculateTotalCost function has several advantages:
- It is simple and easy to understand.
- It is efficient, with a time complexity of O(n), where n is the length of the input arrays.
- It is reusable and can be used in various contexts where you need to calculate the total cost of items.
Conclusion
The calculateTotalCost function is a simple yet effective solution for calculating the total cost of items based on their prices and quantities. Its simplicity, efficiency, and reusability make it a valuable tool for any developer working on an e-commerce application or any other project that requires similar calculations.
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