Tutorial: Using C++ Vectors to Track and Analyze Temperature Samples for a Month

This tutorial demonstrates how to use C++ vector to store and process temperature samples taken randomly throughout the day for an entire month. You’ll learn how to simulate random data, calculate daily statistics (min, max, average), and calculate monthly statistics. The program will use classes to organize the data and computations.

1. Program Overview

The program:

  1. Simulates random temperature samples for each day in a month.
  2. Uses a vector to store temperatures for each day.
  3. Computes:
    • Daily min, max, and average temperatures.
    • Monthly min, max, and average temperatures.

2. Setting Up the Class Structure

We’ll define two classes:

  1. DayTemperature: Handles temperature data and statistics for a single day.
  2. MonthTemperature: Manages temperature data and statistics for the entire month.

3. Code Implementation

Step 1: Include Necessary Libraries

#include <iostream>
#include <vector>
#include <cstdlib> // For rand()
#include <ctime>   // For seeding random numbers
#include <algorithm> // For min_element, max_element, accumulate
using namespace std;

Step 2: Define the DayTemperature Class

class DayTemperature {
private:
    vector temperatures;

public:
    // Constructor to generate random temperatures
    DayTemperature(int samples) {
        for (int i = 0; i < samples; i++) {
            temperatures.push_back((rand() % 800) / 10.0 - 30.0); // Random temperature between -30.0 and 50.0
        }
    }

    // Get daily minimum temperature
    double getMin() const {
        return *min_element(temperatures.begin(), temperatures.end());
    }

    // Get daily maximum temperature
    double getMax() const {
        return *max_element(temperatures.begin(), temperatures.end());
    }

    // Get daily average temperature
    double getAverage() const {
        double sum = accumulate(temperatures.begin(), temperatures.end(), 0.0);
        return sum / temperatures.size();
    }

    // Print daily temperatures (for debugging or visualization)
    void printTemperatures() const {
        for (double temp : temperatures) {
            cout << temp << " ";
        }
        cout << endl;
    }
};

Step 3: Define the MonthTemperature Class

class MonthTemperature {
private:
    vector days;

public:
    // Constructor to generate random temperatures for each day
    MonthTemperature(int daysInMonth, int samplesPerDay) {
        for (int i = 0; i < daysInMonth; i++) {
            days.emplace_back(samplesPerDay); // Add a new DayTemperature object
        }
    }

    // Get monthly minimum temperature
    double getMonthlyMin() const {
        double minTemp = numeric_limits::max();
        for (const DayTemperature& day : days) {
            minTemp = min(minTemp, day.getMin());
        }
        return minTemp;
    }

    // Get monthly maximum temperature
    double getMonthlyMax() const {
        double maxTemp = numeric_limits::lowest();
        for (const DayTemperature& day : days) {
            maxTemp = max(maxTemp, day.getMax());
        }
        return maxTemp;
    }

    // Get monthly average temperature
    double getMonthlyAverage() const {
        double totalSum = 0.0;
        int totalSamples = 0;
        for (const DayTemperature& day : days) {
            totalSum += day.getAverage() * day.getTemperatures().size();
            totalSamples += day.getTemperatures().size();
        }
        return totalSum / totalSamples;
    }

    // Print daily statistics
    void printDailyStats() const {
        for (size_t i = 0; i < days.size(); i++) {
            cout << "Day " << i + 1 << ":\n";
            cout << "  Min: " << days[i].getMin() << "\n";
            cout << "  Max: " << days[i].getMax() << "\n";
            cout << "  Avg: " << days[i].getAverage() << "\n";
        }
    }
};

Step 4: Write the Main Program

int main() {
    srand(time(0)); // Seed random number generator

    const int daysInMonth = 30;
    const int samplesPerDay = 10;

    // Create a MonthTemperature object
    MonthTemperature month(daysInMonth, samplesPerDay);

    // Print daily statistics
    month.printDailyStats();

    // Print monthly statistics
    cout << "\nMonthly Statistics:\n";
    cout << "  Min Temperature: " << month.getMonthlyMin() << "\n";
    cout << "  Max Temperature: " << month.getMonthlyMax() << "\n";
    cout << "  Average Temperature: " << month.getMonthlyAverage() << "\n";

    return 0;
}

4. Explanation

Generating Random Temperatures

  • rand() % 800 / 10.0 - 30.0: Generates a random temperature between -30.0 and 50.0.

Daily Statistics

  • Min: Using std::min_element.
  • Max: Using std::max_element.
  • Average: Using std::accumulate.

Monthly Statistics

  • Loop through all DayTemperature objects to compute the overall min, max, and average temperatures for the month.

5. Example Output

Day 1:
  Min: -12.3
  Max: 28.4
  Avg: 10.1
Day 2:
  Min: -8.7
  Max: 31.2
  Avg: 14.5
...

Monthly Statistics:
  Min Temperature: -15.8
  Max Temperature: 49.3
  Average Temperature: 12.8

6. Practice Enhancements

  1. Modify the program to allow user input for the number of days and samples per day.
  2. Store daily statistics in a separate vector for faster monthly calculations.
  3. Add functionality to output the results to a file.

This program showcases how std::vector can simplify managing and processing data while taking advantage of C++’s powerful algorithms and OOP principles. Experiment with the code and extend it to handle more complex scenarios!

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