View source for C-and-C++/C3/Working-With-2D-Arrays/English

'''Title of script''': Working with 2D arrays

'''Author: Ashwini Patil'''

'''Keywords: ''': 2D arrays, Matrix addition, video tutorial()



{| style="border-spacing:0;"
| style="border-top:0.002cm solid #000000;border-bottom:0.002cm solid #000000;border-left:0.002cm solid #000000;border-right:none;padding:0.097cm;"| <center>'''Visual Cue'''</center>
| style="border:0.002cm solid #000000;padding:0.097cm;"| <center>'''Narration'''</center>

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Slide 1
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Welcome to the spoken-tutorial on '''2dimensional Arrays''' in '''C''' and '''C++.'''

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Slide 2
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| In this tutorial we will learn,

What is a 2Dimensional '''array.'''

We will do this with the help of an example.

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Slide 3
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| To record this tutorial, I am using

'''Ubuntu Operating System''' version 11.10,

'''gcc''' and '''g++''' '''Compiler''' version 4.6.1 on Ubuntu

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Slide 4
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Let us start with the introduction to '''2 dimensional Array'''

'''2-D arrays are stored in a row column matrix.'''

'''The left index indicates the row.'''

'''The right index indicates the column.'''

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'''Starting index of a matrix or array in C and C++ is always 0.'''
Here we see a 2dimensional array in a row column matrix.
Starting index is 0.
|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Slide 5
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Now let us see how to declare '''2 dimensional array'''

The Syntax for this is: 

'''<nowiki>data-type arr_name[row] and [col];</nowiki>'''

eg.here we have declared a 2dimensional array num with 2rows and 3columns.'''<nowiki> int num[2][3];</nowiki>'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| On the editor
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Now let us see an example.

I have already typed the program.

Let me open it.

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Point to array.c
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Note that our file name is '''2d-array.c'''
In this program we will calculate the sum of the elements of the 2dimensional arrays.
Let me explain the code now.
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'''<nowiki>#include <stdio.h></nowiki>'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| This is our '''header file.'''

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Highlight

'''int main()'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| This is our '''main function'''.

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Highlight

'''int i,j;'''



| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Here, we have declared variable '''i''' and '''j'''.

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Highlight

'''<nowiki>int num1[3][4],num2[3][4];</nowiki>'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Then we have declared num1 with 3rows and 4columns

And num2 again with 3rows and 4columns

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'''printf("Enter the elememts of 3X4 array num1\n");'''

'''<nowiki>for(i=0; i<3; i++) </nowiki>'''

'''<nowiki>for(j=0; j<4; j++) </nowiki>'''

'''<nowiki>scanf("%d", &num1[i][j]); </nowiki>'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"|num1 and num2 are 2dimensional arrays.
Here we take elements of the matrix '''num1''' as input from the user.

The elements are stored row-wise.

We have considered i for rows and j for columns.

This for loop will check the condition that i runs from 0 to 2.

This for loop will check the condition that j runs from 0 to 3.

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'''printf("Enter the elememts of 3X4 array num2\n"); '''

'''<nowiki>for(i=0; i<3; i++) </nowiki>'''

'''<nowiki>for(j=0; j<4; j++) </nowiki>'''

'''<nowiki>scanf("%d", &num2[i][j]);</nowiki>'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"|Similarly here we take elements of the matrix '''num2''' as input from the user.


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'''printf("The 3X4 array num1 is\n"); '''

'''<nowiki>for(i=0; i<3; i++) </nowiki>'''

'''{ '''

'''<nowiki>for(j=0; j<4; j++) </nowiki>'''

'''<nowiki>printf("%3d ", num1[i][j]); </nowiki>'''

'''printf("\n"); '''

'''}'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Here we display the matrix num1
Here %3d is used to align the matrix on the terminal.
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'''printf("The 3X4 array num2 is\n"); '''

'''<nowiki>for(i=0; i<3; i++) </nowiki>'''

'''{ '''

'''<nowiki>for(j=0; j<4; j++) </nowiki>'''

'''<nowiki>printf("%3d ", num2[i][j]); </nowiki>'''

'''printf("\n"); '''

'''}'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"|Now here we display the matrix num2 

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'''printf("The sum of num1 and num2 is\n"); '''

'''<nowiki>for(i=0; i<3; i++) </nowiki>'''

'''{ '''

'''<nowiki>for(j=0; j<4; j++) </nowiki>'''

'''<nowiki>printf("%3d ", (num1[i][j] + num2[i][j])); </nowiki>'''

'''printf("\n"); '''

'''}'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Then we add the num1 matrix and the num2 matrix

And display the result

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Highlight

'''return 0;'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| This is our return statement.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Click on Save
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Now, click on '''Save.'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| 
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Let us execute the program.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Press '''Ctrl, Alt and T keys '''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Please open the terminal window by pressing '''Ctrl, Alt''' and '''T''' keys simultaneously on your keyboard.

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| On the terminal

Type

gcc array.c -o arr

./arr
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| To compile type,

gcc space 2d-array.c space -o space arr
and '''Press enter'''

To execute type,

./arr
Now '''Press enter'''

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Enter values


Then Enter the values
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Here we see:

'''Enter the element of 3X4 array num1'''

I will enter the values now.

Now we can see,

'''Enter the elements of 3X4 array num2:'''

I will enter the values. 

The output is displayed. 

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Highlight num1 matrix
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Here we can see the num1 matrix.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Highlight num2 matrix
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Here we can see the num2 matrix.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Highlight the sum.
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| And this is sum of num1 and num2 

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| 
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Now we will see how to execute the same program in C++.

I have already made the program.

I will oepn it and explain.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Point the cursor to the filename

'''2d-array.cpp'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| This is the program for 2D arrays in C++

Note that our file name is 2d-array.cpp

The extension is .cpp. 

Let me explain the code now. 




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'''<nowiki>include<iostream></nowiki>'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| This is our header file as “iostream”.

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Highlight

'''using namespace std'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| This is our “ using” statement.

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'''int main()'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| This is our main function.

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Highlight

'''cout'''

and''' '''

'''cin'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Here we have cout function as we use cout to print the ouput in C++

Then we have “cin ''function.

We use cin to read a line in C++.

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Highlight

'''/t'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Here we use '''''/t''''' it means horizontal tab that is equivalent to 4 spaces.

Rest of the code is similar to our C code. 

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Click on '''Save'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Now click on save.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| On the terminal
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Let us execute come back to our terminal.

Let me clear the prompt.

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Type

'''g++ array.cpp -o arr'''

Type

'''./arr'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| To comple type,

'''g++ space array.cpp space -o space arr1'''

'''Press Enter'''

To execute type

'''./arr1'''

'''Press Enter'''

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Enter values from 1 to 12


Then Enter the values
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Here we see:

'''Enter the element of 3X4 array num1'''

I will enter the values.

Now we see,

'''Enter the elements of 3X4 array num2:'''

I will give the values as 

'''The output is displayed. '''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Highlight

num1 matrix
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| We can see the num1 matrix.

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Highlight

num2 matrix
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| The num2 matrix.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Highlight

The sum
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| And this is sum of num1 and num2 

This brings us to the end of this tutorial.

Come back to our slides

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Summary
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Let us summarize:

In this turoial we learnt,

To add elements in a 2D array.

To print 2D array.

And

To calculate the sum of 2D array.

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| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Assignment
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Write a program that takes two 2D arrays as input.

Subtract them and find the result.

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| style="background-color:transparent;border-top:none;border-bottom:none;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Slide 4

'''About the Spoken Tutorial Project''' 

* Watch the video available at [http://spoken-tutorial.org/What_is_a_Spoken_Tutorial http://spoken-tutorial.org/What_is_a_Sp][http://spoken-tutorial.org/What_is_a_Spoken_Tutorial oken_Tutorial] 

* It summarises the Spoken Tutorial project 

* If you do not have good bandwidth, you can download and watch it 


| style="background-color:transparent;border-top:none;border-bottom:none;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| * Watch the video available at the link shown below

* It summarises the Spoken Tutorial project 

* If you do not have good bandwidth, you can download and watch it 



|-
| style="background-color:transparent;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Slide 5

'''Spoken Tutorial Workshops''' 

The Spoken Tutorial Project Team 

* Conducts workshops using spoken tutorials 

* Gives certificates for those who pass an online test 

* For more details, please write to contact@spoken-tutorial.org 


| style="background-color:transparent;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| The Spoken Tutorial Project Team * Conducts workshops using spoken tutorials 

* Gives certificates for those who pass an online test 

* For more details, please write to contact at spoken hyphen tutorial dot org 



|-
| style="background-color:transparent;border-top:none;border-bottom:none;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Slide 6

'''Acknowledgement''' 

* Spoken Tutorial Project is a part of the Talk to a Teacher project
* It is supported by the National Mission on Education through ICT, MHRD, Government of India 
* More information on this Mission is available at 
* [http://spoken-tutorial.org/NMEICT-Intro http://spoken-tutorial.org/NMEICT-Intro] 


| style="background-color:transparent;border-top:none;border-bottom:none;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Spoken Tutorial Project is a part of the Talk to a Teacher project 
* It is supported by the National Mission on Education through ICT, MHRD, Government of India <br/> More information on this Mission is available at the link shown below
* spoken hyphen tutorial dot org slash NMEICT hyphen Intro 



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| style="background-color:transparent;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Remain on previous slide

No slide for this part
| style="background-color:transparent;border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| This is Ritwik Joshi from IIT Bombay. 

Thank you for joining. 

|}