C Program For Purchased Bakery Items And To Find Their Average

Calculating the average price of purchased bakery items is a common task, whether for personal budgeting or small business management. This process involves collecting the prices of individual items and then computing their mean value.

In this article, you will learn how to write a C program that prompts the user for the number of bakery items, takes their individual prices as input, and then calculates and displays the total cost and the average price.

Problem Statement

Many situations require calculating the average cost of multiple items. For instance, a small bakery owner might want to know the average cost of ingredients for a batch of pastries, or an individual might track their weekly spending on baked goods. The challenge is to efficiently collect a variable number of prices and perform accurate arithmetic to find their sum and average. This can provide valuable insights into spending patterns or ingredient costs.

Example

Here's an example of how the program will interact with the user and display the results:

Enter the number of bakery items purchased: 3
Enter price for item 1: 2.50
Enter price for item 2: 1.75
Enter price for item 3: 3.00

Total cost of bakery items: $7.25
Average price per item: $2.42

Background & Knowledge Prerequisites

To understand and implement this program, readers should have a basic understanding of:

• C Data Types: int for whole numbers and float or double for decimal numbers.
• Input/Output Operations: Using scanf() to read user input and printf() to display output.
• Loops: Specifically, the for loop to iterate a fixed number of times.
• Variables: Declaring and assigning values to variables.
• Basic Arithmetic Operators: Addition (+) and division (/).

Use Cases or Case Studies

Calculating averages is a fundamental operation with wide applicability. Here are a few practical examples for this specific scenario:

• Personal Budgeting: Track the average cost of your daily coffee and pastry to understand your spending habits.
• Small Business Inventory: A cafe owner can calculate the average cost of different types of bread purchased from a supplier to inform pricing strategies.
• Educational Tool: Students learning C programming can use this as a simple, practical exercise to grasp loops, input, and basic calculations.
• Event Planning: If catering a small event with assorted baked goods, calculate the average cost per guest for the bakery portion.
• Comparative Shopping: Compare the average price of bakery items across different stores to find the most economical option.

Solution Approaches

For calculating the average of a series of numbers, the most straightforward approach involves summing all the numbers and then dividing by their count.

Approach: Calculating Average Price of Bakery Items

This approach uses a for loop to collect prices one by one, accumulates their sum, and then computes the average after all inputs are received.

// Calculate Average Price of Bakery Items
#include <stdio.h> // Required for input/output functions like printf and scanf

int main() {
    // Step 1: Declare necessary variables
    int numberOfItems;      // To store the count of bakery items
    float itemPrice;        // To store the price of each individual item
    float totalCost = 0.0;  // To accumulate the sum of all item prices, initialized to 0
    float averagePrice;     // To store the calculated average price

    // Step 2: Prompt the user to enter the number of bakery items
    printf("Enter the number of bakery items purchased: ");
    scanf("%d", &numberOfItems); // Read the integer value into numberOfItems

    // Step 3: Use a loop to get the price for each item
    // The loop will run 'numberOfItems' times
    for (int i = 1; i <= numberOfItems; i++) {
        printf("Enter price for item %d: ", i); // Prompt for the price of the current item
        scanf("%f", &itemPrice);                // Read the float value into itemPrice
        totalCost += itemPrice;                 // Add the current item's price to totalCost
    }

    // Step 4: Calculate the average price
    // Check to prevent division by zero if no items were entered
    if (numberOfItems > 0) {
        averagePrice = totalCost / numberOfItems;
        // Step 5: Display the total cost and average price
        printf("\\nTotal cost of bakery items: $%.2f\\n", totalCost); // .2f for 2 decimal places
        printf("Average price per item: $%.2f\\n", averagePrice);
    } else {
        printf("\\nNo items were entered, so average cannot be calculated.\\n");
    }

    return 0; // Indicate successful execution of the program
}

Run

Sample Output

Enter the number of bakery items purchased: 4
Enter price for item 1: 1.50
Enter price for item 2: 2.25
Enter price for item 3: 1.75
Enter price for item 4: 3.00

Total cost of bakery items: $8.50
Average price per item: $2.13

Stepwise Explanation

1. Include Header: The #include line includes the standard input/output library, providing functions like printf for printing to the console and scanf for reading user input.
2. Declare Variables:

• numberOfItems (an int) stores how many items the user purchased.
• itemPrice (a float) temporarily holds the price of each item as it's entered.
• totalCost (a float) accumulates the sum of all item prices. It's initialized to 0.0.
• averagePrice (a float) stores the final calculated average.

1. Get Item Count: The program prompts the user to enter the total number of bakery items and reads this integer using scanf("%d", &numberOfItems).
2. Loop for Prices: A for loop iterates from 1 up to numberOfItems. In each iteration:

• It prompts the user to enter the price for the current item (item %d).
• It reads the floating-point price using scanf("%f", &itemPrice).
• It adds the itemPrice to totalCost.

1. Calculate Average: After the loop finishes, the program checks if numberOfItems is greater than 0 to avoid division by zero. If valid, averagePrice is calculated by dividing totalCost by numberOfItems.
2. Display Results: Finally, printf is used to display both the totalCost and averagePrice, formatted to two decimal places using %.2f.
3. Return 0: The return 0; statement indicates that the program executed successfully.

Conclusion

This C program provides a simple yet effective solution for calculating the total and average price of a variable number of bakery items. It demonstrates fundamental C programming concepts such as variable declaration, input/output operations, and loop structures. This basic framework can be extended for more complex inventory or budgeting applications.

Summary

• Initialize Variables: Set up int for item count and float for prices and totals.
• Get Item Count: Prompt the user for the total number of items to process.
• Loop for Prices: Use a for loop to repeatedly ask for each item's price and accumulate the totalCost.
• Calculate Average: Divide totalCost by the numberOfItems to find the averagePrice, ensuring to handle cases with zero items.
• Display Results: Print the calculated totalCost and averagePrice in a user-friendly format.