1D and 2D arrays

Содержание

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Цель обучения (Learning objectives): write program code using 1D and 2D arrays for different data types

Цель обучения (Learning objectives):

write program code using 1D and 2D arrays

for different data types
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Критерии успеха (Successful criteria): Knows and understands the purpose of the

Критерии успеха (Successful criteria):

Knows and understands the purpose of the data

type array
Knows the concepts of array name, array dimension, element index, array elements, array element types
Can declare the data type of an array in a variable section
Can perform input / output of array elements
Can use array data types when solving problems
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Questions for discussion What are arrays? How to determine the name

Questions for discussion

What are arrays?
How to determine the name of the

array, the dimension of the array, the index of the element, the elements of the array, the types of elements of the array.
How to declare an array data type in a variable section
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An array is similar to a table of objects or primitive

An array is similar to a table of objects or primitive

types, keyed by index.

1D Array: Students

1D Array: Marks

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An array is a named set of the same type of

An array is a named set of the same type of

data that is stored in memory consecutively one after the other.
Access to the elements of the array is carried out by the index (number) of the element.
An array can contain elements of any data type (integer, real, character, string).
The number of elements in an array is called the size of the array.
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Declaration of an array in the variable section [] ; Examples:

Declaration of an array in the variable section

[]

; Examples:
int[] a1; char[] ch1; double[] db1;

Indexing arrays starts from zero, so the index of the first element of the array is 0.
The array element is accessed via square brackets [].
For example: A [0] = 5

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Initializing array elements 1 variant int [] к; //к — array

Initializing array elements

1 variant int [] к; //к — array k= nеw int

[3]; //Define an array of 3 integers
к[0]=-5; к[1]=4; к[2]=55; // Set array elements 2 variant int[] а = {0, 2, 4, 6, 8}; 3 variant int[] а = nеw int [] {0, 2, 4, 6, 8}; 4 variant int[] а=nеw int[5]; а[0] = 0; а[1] = 2; а[2] = 4; а[3] = 6; а[4] = 8;
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Task: One-dimensional array is given. You need to calculate the sum

Task: One-dimensional array is given. You need to calculate the sum

of the elements of this array.
public partial class Form1 : Form
{ int [] mas = new int [] { 1, 3, 5, 7, 9, 4, 8, 2, 6, 10 }; //Creating an array with values
private void button1_Click(object sender, EventArgs e)
{
listBox1.Items.Clear(); // clear
for (int i = 0; i < 10; i++)
{
listBox1.Items.Add(mas[i]);
}
}
private void button2_Click_1(object sender, EventArgs e)
{
listBox1.Items.Clear();
int s=0;
for (int i = 0; i < 10; i++)
{
s=s+mas[i];
}
listBox1.Items.Add(s);
}
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Task: One-dimensional array is given. You need to calculate the sum

Task: One-dimensional array is given. You need to calculate the sum

of the elements of this array. The value of the elements is set randomly.
private void button1_Click(object sender, EventArgs e)
{
Random rd = new Random();
int[] mass = new int[5];
int i, s = 0;
for (i = 0; i {
mass[i] = rd.Next(5);
s = s + mass[i];
listBox1.Items.Add(mass[i]);
}
label1.Text = Convert.toString(s);
}
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Exercise #1 1D Array: Students 1D Array: Marks Call me value of: Marks[3] Students[0] Students[1]+’ ‘+Marks[1]

Exercise #1

1D Array: Students

1D Array: Marks
Call me value of: Marks[3] Students[0]
Students[1]+’ ‘+Marks[1]

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Exercise #2 Explain every part of next line: { int []

Exercise #2
Explain every part of next line:
{ int

[] mas = new int [] { 1, 3, 5, 7, 9, 4, 8, 2, 6, 10 };

2

1 3


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Exercise #2 – data type of array elements – name of

Exercise #2

– data type of array elements
– name of array
3 –

array element values
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Exercise #3 Describe list (Pen, Pencil, Copybook, Eraser) in С# using type array.

Exercise #3

Describe list (Pen, Pencil, Copybook, Eraser) in С# using type

array.
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Exercise #4 Fill ten array elements random numbers [-20; 20] www.bzfar.net

Exercise #4

Fill ten array elements random numbers [-20; 20]

www.bzfar.net

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Exercise #5 Output ten array elements in line in a space. Write fragment of code. www.bzfar.net

Exercise #5

Output ten array elements in line in a space.
Write fragment

of code.

www.bzfar.net

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QQQ What is the output of the following code: array primes

QQQ

What is the output of the following code:

array primes = (2,3,5,7,11,13,17,19,23)
count

= 8
While count >= 0 write(primes[count] , “, “ ) count = count - 1
end while

Output: 23,19,17,13,11,7,5,3,2

www.bzfar.net

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One dimensional array on Wikibooks www.bzfar.net https://en.wikibooks.org/wiki/A-level_Computing/AQA/Paper_1/Fundamentals_of_data_structures/Arrays

One dimensional array on Wikibooks

www.bzfar.net

https://en.wikibooks.org/wiki/A-level_Computing/AQA/Paper_1/Fundamentals_of_data_structures/Arrays

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Two dimensional array (Matrix) Most major programming languages allow you to

Two dimensional array (Matrix)

Most major programming languages allow you to use

two- dimensional arrays. They work in much the same way as a one-dimensional array but allow you to specify a column index and a row index.
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Declaration int [,] mas = new int[5,5]; int[,] mas = new

Declaration

int [,] mas = new int[5,5];
int[,] mas = new

int[3, 3] { { 4, 7, 3 }, { 3, 6, 9 }, { 0, 1, 4 } };
int[,] mas = { { 4, 7, 3 }, { 3, 6, 9 }, { 0, 1, 4 } };
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Assign Values to Two Dimension a[0,0] = 76; a[0,1] = ?

Assign Values to Two Dimension

a[0,0] = 76;
a[0,1] = ?
a[1,0]= ?

a[1,1] = ?
a[2,0] = ?
a[2,2] = ?
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Two dimensional arrays on wikibooks www.bzfar.net https://en.wikibooks.org/wiki/A- level_Computing/AQA/Problem_Solving, _Programming,_Data_Representation_a nd_Practical_Exercise/Fundamentals_of _Programming/Two-Dimensional_Arrays

Two dimensional arrays on wikibooks

www.bzfar.net

https://en.wikibooks.org/wiki/A-
level_Computing/AQA/Problem_Solving,
_Programming,_Data_Representation_a nd_Practical_Exercise/Fundamentals_of
_Programming/Two-Dimensional_Arrays