Algorithms. Development of Programming Logic

In this class I will propose a simple exercise that will force you to think of an ingenious solution. This type of situation will initiate your development of programming logic.

The code for this class is here:

int subAlg(int a, int b) {

    int value = 0;

    while (a > b) {

        b++;

        value++;

    }

    return value;

}

In this class we continue developing algorithms based on the previous class.

The code of this class is here:

int mulAlg(int a, int b) {

    int value = 0;

    while (a) {

        a--;

        value += b;

    }

    return value;

}

In this class we develop more complicated algorithms and at the same time I recommend some websites where you can learn from the code of other professional experts.

The code of this class is here:

int divAlg(int a, int b) {

    int value = 0;

    while (a>=b) {

        value++;

        a -= b;

    }

    cout << "15 / 3 = " << value << "(" << a <<  ")" << endl;

    return value;

}

In this class we will see how a known exercise can be VERY MUCH optimized. Here you will acquire the essential habit of optimization.

The code for this class is here:

void verifyPrime(int number) {

    bool prime = true;

    for (int i = 2; i <= number/2 && prime; i++) {

        if (number % i == 0) prime = false;

    }

    if (prime) cout << number << " is prime" << endl;

    else cout << number << " is not prime" << endl;

}

Before explaining each of the algorithms we will see, we will have an overview of this section. In this class we will talk about why sorting algorithms are important and we will make a comparison between them.

In this class I will explain the logic behind the Bubble Sort algorithm to help you understand this sorting method. After watching this video I encourage you to try to code the algorithm. And then in the next class you will be able to check how I have done it. In this way you can test your skills and perfect your ability to convert logical thinking about solving a problem into code.

In this class we will see the code implementation of the BubbleSort algorithm with the exact explanation of what each line and element of the code does (part 1).

The code of this class is here:

void byBubbleSort() {

    //int v[] = { 2,7,1,4,3,5,0,8,2,-1,2 };

    int v[] = { 7, 28, 2, 53, 16, 13, 45, 345, 2345, 234, 35235 ,123, 4346,75, 4,7,3,68,2,6,63,2,0,68,436,12,343,54,25, 13, 15, 2, 97, 81, 981 ,618 ,61, 3280, 18, 5, 78, 23, 81, 65, 84, 72, 95 };

    int size = sizeof(v) / sizeof(*v);

    int aux;

    int rounds = 0;

    bool ord = false;

    cout << endl;

    for (int i = 0; i < size; i++) cout << v[i] << " ";

    while (!ord) {

        ord = true;

        for (int i = 0; i < size - 1 - rounds; i++) {

            if (v[i] > v[i + 1]) {

                aux = v[i + 1];

                v[i + 1] = v[i];

                v[i] = aux;

                ord = false;

            }

        }

        rounds++;

    }

    cout << endl;

    for (int i = 0; i < size; i++) cout << v[i] << " ";

}

In this class we will see the code implementation of the Bubble Sort algorithm with the exact explanation of what each line and element of the code does (part 2).

The code of this class is here

void byBubbleSort() {

    //int v[] = { 2,7,1,4,3,5,0,8,2,-1,2 };

    int v[] = { 7, 28, 2, 53, 16, 13, 45, 345, 2345, 234, 35235 ,123, 4346,75, 4,7,3,68,2,6,63,2,0,68,436,12,343,54,25, 13, 15, 2, 97, 81, 981 ,618 ,61, 3280, 18, 5, 78, 23, 81, 65, 84, 72, 95 };

    int size = sizeof(v) / sizeof(*v);

    int aux;

    int rounds = 0;

    bool ord = false;

    cout << endl;

    for (int i = 0; i < size; i++) cout << v[i] << " ";

    while (!ord) {

        ord = true;

        for (int i = 0; i < size - 1 - rounds; i++) {

            if (v[i] > v[i + 1]) {

                aux = v[i + 1];

                v[i + 1] = v[i];

                v[i] = aux;

                ord = false;

            }

        }

        rounds++;

    }

    cout << endl;

    for (int i = 0; i < size; i++) cout << v[i] << " ";

}

In this class I will explain the logic behind the Selection algorithm so that you can understand this sorting method. After watching this video I encourage you to try to code the algorithm. And then in the next class you will be able to check how I have done it. In this way you can test your skills and perfect your ability to convert logical thinking about solving a problem into code.

Code Implementation of Algorithm by Selection Part 1

In this class we will see the coding step of the Selection algorithm with the exact explanation of what each line and element of the code does.

The code of this class is here

void bySelectionSort() {

    //int v[] = { 2,7,1,4,3,5,0,8,2,-1,2 };

    int v[] = { 7, 28, 2, 53, 16, 13, 45, 345, 2345, 234, 35235 ,123, 4346,75, 4,7,3,68,2,6,63,2,0,68,436,12,343,54,25, 13, 15, 2, 97, 81, 981 ,618 ,61, 3280, 18, 5, 78, 23, 81, 65, 84, 72, 95 };

    int size = sizeof(v) / sizeof(*v);

    int aux;

    int PosMin;

    cout << endl;

    for (int i = 0; i < size; i++) cout << v[i] << " ";

    for (int i = 0; i < size; i++) {

        PosMin = i;

        for (int j = i + 1; j < size; j++) {

            if (v[PosMin] > v[j])

                PosMin = j;

        }

        aux = v[i];

        v[i] = v[PosMin];

        v[PosMin] = aux;

    }

    cout << endl;

    for (int i = 0; i < size; i++) cout << v[i] << " ";

}

Code Implementation of Algorithm by Selection Part 2

In this class we will see the coding step of the Selection algorithm with the exact explanation of what each line and element of the code does.

The code of this class is here

void bySelectionSort() {

    //int v[] = { 2,7,1,4,3,5,0,8,2,-1,2 };

    int v[] = { 7, 28, 2, 53, 16, 13, 45, 345, 2345, 234, 35235 ,123, 4346,75, 4,7,3,68,2,6,63,2,0,68,436,12,343,54,25, 13, 15, 2, 97, 81, 981 ,618 ,61, 3280, 18, 5, 78, 23, 81, 65, 84, 72, 95 };

    int size = sizeof(v) / sizeof(*v);

    int aux;

    int PosMin;

    cout << endl;

    for (int i = 0; i < size; i++) cout << v[i] << " ";

    for (int i = 0; i < size; i++) {

        PosMin = i;

        for (int j = i + 1; j < size; j++) {

            if (v[PosMin] > v[j])

                PosMin = j;

        }

        aux = v[i];

        v[i] = v[PosMin];

        v[PosMin] = aux;

    }

    cout << endl;

    for (int i = 0; i < size; i++) cout << v[i] << " ";

}

Part 1 of the Creating Your Own Sorting Algorithm Project

In this video I will explain the algorithm I have personally developed for sorting data and the corresponding implementation in code.

Please try to create your own algorithm and share your code! :)

Part 2 of Creating Your Own Sorting Algorithm Project

In this video I will explain the algorithm I have personally developed for sorting data and the corresponding implementation in code.

Please try to create your own algorithm and share your code! :)

Part 3 of Creating Your Own Sorting Algorithm Project

In this video I will explain the algorithm I have personally developed for sorting data and the corresponding implementation in code.

Please try to create your own algorithm and share your code! :)

The code for this class is here

void byJJ() {

    unsigned t0, t1;

    t0 = clock();

    //int v[] = { 2,7,1,4, 5,8,0};

    int v[] = { 7, 28, 2, 53, 16, 13, 45, 345, 2345, 234, 35235 ,123, 4346,75, 4,7,3,68,2,6,63,2,0,68,436,12,343,54,25, 13, 15, 2, 97, 81, 981 ,618 ,61, 3280, 18, 5, 78, 23, 81, 65, 84, 72, 95 };

    int size = sizeof(v) / sizeof(*v);

    int aux;

    int PosMin;

    int PosMax;

    int PosFinal;

    PosFinal = size - 1;

    cout << endl;

    for (int i = 0; i < size; i++) cout << v[i] << " ";

    for (int i = 0; i < size / 2; i++) {

        PosMin = i;

        PosMax = i;

        for (int j = i; j <= PosFinal; j++) {

            if (v[j] > v[PosMax]) PosMax = j;

            if (v[j] < v[PosMin]) PosMin = j;

        }

        aux = v[PosMin];

        v[PosMin] = v[i];

        v[i] = aux;

        if (PosMax == i) PosMax = PosMin;

        aux = v[PosFinal];

        v[PosFinal] = v[PosMax];

        v[PosMax] = aux;

        PosFinal--;

        //cout << endl;

        //for (int n = 0; n < size; n++) cout << v[n] << " ";

    }

    cout << endl;

    for (int i = 0; i < size; i++) cout << v[i] << " ";

    t1 = clock();

    double time = (double(t1 - t0) / CLOCKS_PER_SEC);

    cout << endl << endl << "Execution Time byJJ: " << time << endl;

}

Before closing the algorithms section I give you some tips to further develop your programming skill