Lesson # 5. Methods or Functions in C sharp

To do: Three numbers are entered, they are the lengths of the triangle’s three sides. Create a Perimeter function that calculates the perimeter of a triangle based on the lengths of its three sides.
  
Note 1: Perimeter() method must accept three integers as arguments.

Note 2: The method must return no value which is why you have to use void in the signature:

static void Perimeter(...);

Note 3: Don’t forget to convert the entered values into integers. For example:

int a = int.Parse(Console.ReadLine());

  
Expected output:

Please enter the 3 sides of the triangle:
3 5 6
The perimeter is: 14

[Solution and Project name: Lesson_5Task1, file name L5Task1.cs]

To do: Modify the previous task. Now the Perimeter function must return an integer value. We remind you of the task: Three numbers are entered, they are the lengths of the triangle’s three sides. Create a Perimeter function that calculates the perimeter of a triangle based on the lengths of its three sides.
  
Note 1: Perimeter() method must accept three integers as arguments.

Note 2: The method must return an integer value which is why you have to use int in the signature:

static int Perimeter(...);

Note 3: Don’t forget to convert the entered values into integers:

int a = int.Parse(Console.ReadLine());

  
Expected output:

Please enter the 3 sides of the triangle:
3 5 6
The perimeter is: 14

[Solution and Project name: Lesson_5Task2, file name L5Task2.cs]

To do: Create a Distance function that calculates a distance between two points on the plane, the coordinates of the points are entered (the variables x1,y1 for the first point and x2,y2 for the second).
  
Note 1: The Distance() method must accept four integers as arguments (the coordinates of the points).

Note 2: The method must return no value which is why you have to use void in the signature:

static void Distance(...);

Note 3: To calculate the distance between two points you have to use the formula:

// square root: 
Math.Sqrt(...);
// the power of a number: 
Math.Pow(number, power);

  
Expected output:

Please enter the coordinates of two points (four integers: x1, y1, x2, y2):
1 -2  4  2
The distance is: 5

[Solution and Project name: Lesson_5Task3, file name L5Task3.cs]

To do: Modify the previous task. Now the Distance function must return a double value. We remind you of the task: Create a Distance function that calculates a distance between two points on the plane, the coordinates of the points are entered (variables x1,y1 for the first point and x2,y2 for the second).
  
Note: The method must return a double value which is why you have to use double in the signature:

static double Distance(...);

  
Expected output:

Please enter the coordinates of two points (four integers: x1, y1, x2, y2):
3.2   3.4  8  7.1  
The distance is: 6.0605

[Solution and Project name: Lesson_5Task4, file name L5Task4.cs]

To do: A two-digit integer is entered. Create ChangeDigits() method that takes an entered argument by reference and changes its value so that the first digit of a new number is the second digit of the input number, and vice versa, the second digit of a new number is the first digit of the input number. For example, if 45 is entered, the resulting number will be 54.
  
Note 1: The ChangeDigits() method must take an integer by reference as an argument.
Note 2: The method doesn’t return any value, which is why you have to use void in the signature:

static void ChangeDigits(...);

Note 3: First, you have to get the digits of the number. Then, you have to make a number of the resulting digits by swapping them. To make a number of two digits use the example:

if we have 2, 3
2*10 + 3 = 23

  
Expected output:

Please enter two-digit number:
58
The result is: 85

  
[Solution and Project name: Lesson_5Task5, file name L5Task5.cs]

To do: Two two-digit integers are entered. Create a BitwiseSum function that calculates their bitwise sum modulo 10. For example, the bitwise sum of the numbers 34 and 59 is the number 83 (3 + 5 = 8; 4 + 9 = 13, 13%10 = 3).
  
Note 1: The BitwiseSum() method must take two integers as arguments.

Note 2: The method must return an integer value which is why you have to use int in the signature:

static int BitwiseSum(...);

Note 3: First, you have to get the digits of the number. Then, calculate the bitwise sum modulo 10 of the digits. Afterward, you have to make a number of the resulting digits. To make a number of two digits use the example:

if we have 2, 3
2*10 + 3 = 23

Expected output:

Please enter two two-digit numbers:
34 59
The bitwise sum of 34 and 59 is: 83

  
[Solution and Project name: Lesson_5Task6, file name L5Task6.cs]

To do: Create PosNegSeq() method that takes two integer arguments by reference, they are counters for positive and negative values of the entered sequence. User must input the sequence of integers and finish the inputting by entering 0. The method has to count positive and negative of the entered numbers and return the values of counters to the main function.

Note 1: The method returns no value (which is why you have to use void in signature). ref arguments are input-output arguments, which means that their values are changed within the method and passed from within the method to the main program.

Note 2: A ref arguments have to be initialized before the calling of the function. So, first, you have to do is to initialize the arguments. The start value for the counters — the arguments of the function — is 0:

...
int counterPositive = 0;
int counterNegative = 0;
...

  
  
Expected output:

Please enter the sequence, input 0 when it ends
2  -4  8  -3  5  0
counter for positive is: 3, counter for positive is: 2

[Solution and Project name: Lesson_5Task7, file name L5Task7.cs]

To do: Create a MaxMinSeq() method with two integer arguments, they are needed to store the minimum and maximum values of the entered sequence. User must input the sequence of integers and finish the inputting by entering 0. The method has to find a minimum and maximum and return them to the Main function.

Note 1: Use out parameters by reference to return two values from a function. You don’t need to inisialize the parameteres before calling the function:

int max, min;
MaxMinSeq(out max, out min);

Note 2: Since we use out parameters, which are not needed to be initialized before the calling the function, so they must be initialized within the fucntion.

Expected output:

Please enter the sequence, input 0 when it ends
2  4  8  3  0
minimum is: 2, maximum is: 8

[Solution and Project name: Lesson_5Task8, file name L5Task8.cs]

To do: Create a new project. Add a new class-file to the project. Create a method within this class to calculate the following sequence: 1 + A + A2 + A3 + … + AN. A must be entered double number. N is entered integer greater than 0. You shouldn’t use a standard pow() method; to calculate the power of the numbers you should use loop.

Expected output:

Enter A: 1,5
Enter N: 6
The sequence sum is: 32,171875

[Solution and Project name: Lesson_5Task9, file name L5Task9.cs]

To do: Create a FloorCubicRoot function that finds the largest integer that does not exceed the cubic root of the specified number (Math.Pow, Math.Floor).

Note: You can calculate the cubic root of the number x in the wolframalpha service using the query x1/3, for example: 15.625^1/3 (the answer is 2.5).
  
Expected output:

Please enter a number:
15,625
The result is 2.5 : 15.625 ^ 1/3

  
[Solution and Project name: Lesson_5ExTask1, file name L5ExTask1.cs]

To do: A real number A and an integer N (≥ 0) are entered. Create a function SumOfSeq() which finds the sum of:

1 + A + A2 + A3 + ... + AN

Note 1: Within a function, there has to be the only loop.

Note 2: Do not use standard pow function for the degree, accumulate the values of degrees using a loop.

Expected output:

Please enter a double A and an integer N:
2.2  3
Sum of elements of the sequence of powers of the number 2.2 from 0 to 3: 18.688

[Solution and Project name: Lesson_5ExTask2, file name L5ExTask2.cs]