Coding Practice — How to Think Like a Computer Scientist

There are errors in the code below. Modify the code so that main runs successfully. Select the Parsonsprob tab for hints for the construction of the code.

There are errors in the code below. Modify the code so that main runs successfully. Use the lines to construct the code, then go back to complete the Activecode tab.

        class Room {
    private:
        int length;
        int width;
        int height;
---
    public:
        int calculateArea () {
            return length * width;
        }
---
        int calculateVolume () {
            return length * width * height;
        }
---
        void setLength (int l) {
            length = l;
        }
---
        int getLength () const {
            return length;
        }
---
        void setWidth (int w) {
            width = w;
        }
---
        int getWidth () const {
            return width;
        }
---
        void setHeight (int h) {
            height = h;
        }
---
        int getHeight () const {
            return height;
        }
---
};
---
int main() {
---
    Room r;
---
    r.setLength(12);
---
    r.setWidth(14);
---
    r.setHeight(10);
---
    cout << "The room with dimensions " << r.getLength() << ", " << r.getWidth()
        << ", and " << r.getHeight() << " has an area of " << r.calculateArea()
        << " and a volume of " << r.calculateVolume() << endl;
---
}

In main create a Temp object to calculate what 100 degrees Celsius is in Fahrenheit. Select the Parsonsprob tab for hints for the construction of the code.

#include <iostream>
using namespace std;

class Temp {
    private:
        double fahrenheit;
        double celsius;
        bool is_fahrenheit;
        bool is_celsius;

double cToF() {
            return celsius * 9/5 + 32;
        }

double fToC() {
            return (fahrenheit - 32) * 5/9;
        }

public:
        double getFahrenheit () {
            if (is_celsius) { return cToF(); }
            else { return fahrenheit; }
        }
        double getCelsius () {
            if (is_fahrenheit) { return fToC(); }
            else { return celsius; }
        }
        void setFahrenheit (double f) { fahrenheit = f; is_fahrenheit = true; is_celsius = false; }
        void setCelsius (double c) { celsius = c; is_celsius = true; is_fahrenheit = false; }
        void printTemp () {
            if (is_fahrenheit) {
                cout << "It is " << getFahrenheit() << " degrees Fahrenheit" << endl;
            }
            else {
                cout << "It is " << getCelsius() << " degrees Celsius" << endl;
            }
        }
};

int main() {
    // Write your code here.
}

In main create a Temp object to calculate what 100 degrees Celsius is in Fahrenheit. Use the lines to construct the code, then go back to complete the Activecode tab.

        int main() {
---
    Temp t;
---
    t.setCelsius(100);
---
    t.setFahrenheit(t.getFahrenheit());
---
    t.printTemp();
---
}

What if we had an existing vector with data that we want to copy into our MyVector? Write a constructor that takes a vector and copies the data into the elements vector. Select the Parsonsprob tab for hints for the construction of the code.

What if we had an existing vector with data that we want to copy into our MyVector? Write a constructor that takes a vector and copies the data into the elements vector. Use the lines to construct the code, then go back to complete the Activecode tab.

        MyVector (vector vec) {
---
   elements = vec;
---
}

Now we can write some of our own fun functions! No longer do we need to write for loops every time we want to print out a vector. With MyVector, we can just call the member function print! Write the MyVector member function print, which prints out the contents of MyVector. For example, if our MyVector contained the elements 2, 5, 1, and 8, print should print out [2, 5, 1, 8] followed by a newline. Select the Parsonsprob tab for hints for the construction of the code.

Now we can write some of our own fun functions! No longer do we need to write for loops every time we want to print out a vector. With MyVector, we can just call the member function print! Write the MyVector member function print, which prints out the contents of MyVector. For example, if our MyVector contained the elements 2, 5, 1, and 8, print should print out [2, 5, 1, 8] followed by a newline. Use the lines to construct the code, then go back to complete the Activecode tab.

        void print() {
---
   cout << "[";
---
   for (size_t i = 0; i < elements.size() - 1; ++i) {
---
       cout << elements[i] << ", ";
---
   }
---
   cout << elements[elements.size() - 1] << "]" << endl;
---
}

What if we wanted to return the largest and smallest elements in our MyVector? Write the public member functions max and min which calls the private member functions findMax and findMin. findMax and findMin return the indices of the max and min values, and max and min call these private member functions and return the max and min values. Select the Parsonsprob tab for hints for the construction of the code.

#include <iostream>
#include <vector>
using namespace std;

class MyVector {
    private:
        vector<int> elements;

// Write your findMax function here.

// Write your findMin function here.

public:
        MyVector() {};
        MyVector(vector<int> vec);

size_t size();
        void push_back(int value);
        void pop_back();
        int at(int index);
        void print();
        void push_front(int value);
        void pop_front();
};

// Write your max function here.

// Write your min function here.

int main() {
    vector<int> vec = { 8, 1, 5, 87, 23, 64 };
    MyVector myVec(vec);
    cout << "The largest element is " << myVec.max() << endl;
    cout << "The smallest element is " << myVec.min() << endl;
}
====
MyVector::MyVector (vector<int> vec) {
    elements = vec;
}

size_t MyVector::size() { return elements.size(); }

void MyVector::push_back(int value) { elements.push_back(value); }

void MyVector::pop_back() { elements.pop_back(); };

int MyVector::at(int index) { return elements[index]; }

void MyVector::print() {
    cout << "[";
    for (size_t i = 0; i < elements.size() - 1; ++i) {
        cout << elements[i] << ", ";
    }
    cout << elements[elements.size() - 1] << "]" << endl;
}

void MyVector::push_front(int value) {
    vector<int> temp;
    temp.push_back(value);
    for (size_t i = 0; i < elements.size(); ++i) {
        temp.push_back(elements[i]);
    }
    elements = temp;
}

void MyVector::pop_front() {
    for (size_t i = 1; i < elements.size(); ++i) {
        elements[i - 1] = elements[i];
    }
    elements.pop_back();
}

What if we wanted to return the largest and smallest elements in our MyVector? Write the public member functions max and min which calls the private member functions findMax and findMin. findMax and findMin return the indices of the max and min values, and max and min call these private member functions and return the max and min values. Use the lines to construct the code, then go back to complete the Activecode tab. Be sure to declare the max and min functions in public when you complete the Activecode.

        // findMax private member function
int findMax (vector vec) {
---
    int inMax;
---
    int max = vec[0];
---
    for (size_t i = 0; i < vec.size() - 1; i++) {
---
        if (vec[i] > max) {
---
            max = vec[i];
---
            inMax = i;
---
        }
---
    }
---
    return inMax;
---
}
---
// findMin private member function
int findMin (vector vec) {
---
    int inMin;
---
    int min = vec[0];
---
    for (size_t i = 0; i < vec.size(); i++) {
---
        if (vec[i] < min) {
---
            min = vec[i];
---
            inMin = i;
---
        }
---
    }
---
    return inMin;
---
}
---
// max public member function
int MyVector::max () {
---
    return elements[findMax(elements)];
---
}
---
// min public member function
int MyVector::min () {
---
    return elements[findMin(elements)];
---
}

Coding Practice¶