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

Title of script:

Author: Ashwini Patil

Keywords:

Visual Cue	Narration
Slide 1	Welcome to the spoken-tutorial on 2dimensional Arrays in C and C++.
Slide 2	In this tutorial we will learn, What is an 2D array. We will do this with the help of an example.
Slide 3	To record this tutorial, I am using Ubuntu Operating System version 11.04, gcc and g++ Compiler version 4.6.1 on Ubuntu
Slide 4	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. 0 1 2 3 1 2 3 4 5 6 7 8 9 10 11 12 We can visualize a 2-D array in the form of a matrix. Matrix is composed of multiple rows and horizontal columns. Starting index of a matrix or array in C and C++ is always 0.
Slide 5	Let us see how to declare 2 dimensional array The Syntax for this is: data-type arr_name[row] [col]; eg. int num[2][3];
On the editor	Now let us see how to declare an 2D array through an example. I have already typed the program on the editor. So, I will open it. Let me explain the program.
Point to array.c	Note that our file name is 2d-array.c
Highlight #include <stdio.h>	This is our header file.
Highlight int main()	This is our main function.
Highlight int i,j;	Here, we have declared variable i and j.
Highlight int num1[3][4],num2[3][4];	Here we have declared num1 with 3rows and 4columns And num2 with 3rows and 4columns
Highlight printf("Enter the elememts of 3X4 array num1\n"); for(i=0; i<3; i++) for(j=0; j<4; j++) scanf("%d", &num1[i][j]);	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. We have considered 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.
Highlight printf("Enter the elememts of 3X4 array num2\n"); for(i=0; i<3; i++) for(j=0; j<4; j++) scanf("%d", &num2[i][j]);	Here we take elements of the matrix num2 as input from the user.
Highlight printf("The 3X4 array num1 is\n"); for(i=0; i<3; i++) { for(j=0; j<4; j++) printf("%3d ", num1[i][j]); printf("\n"); }	Here we display the matrix num1
Highlight printf("The 3X4 array num2 is\n"); for(i=0; i<3; i++) { for(j=0; j<4; j++) printf("%3d ", num2[i][j]); printf("\n"); }	Here we display the matrix num2
Highlight printf("The sum of num1 and num2 is\n"); for(i=0; i<3; i++) { for(j=0; j<4; j++) printf("%3d ", (num1[i][j] + num2[i][j])); printf("\n"); }	Here, we add the num1 matrix and the num2 matrix Then we display the result
Highlight return 0;	This is our return statement.
Click on Save	Now, click on Save.
	Let us execute the program.
Press Ctrl, Alt and T keys	Please open the terminal window by pressing Ctrl, Alt and T keys simultaneously.
On the terminal Type gcc array.c -o arr ./arr	To compile type, gcc 2d-array.c -o 2darr To execute type, ./2darr
	Now let us see how to execute the same program in C++.
On the editor	Come back to our program.
	I will change a few things here.
Click on File menu Click on Save as option	First click on File menu, Click on Save as option, Save the file with .cpp extension.
Type iostream	First lets change the header file as iostream
Type using namespace std;	Let us include the using statement.
Type cout <<	Now replace the printf statement with the cout statement. Here, \t mean horizontal tab that is equivalent to 4 spaces.
Type cin >>	Replace the scanf statement with the cin statement.
Click on Save	Now click on Save
	Let us execute the program and see
On the terminal	Come back to the terminal
Type g++ array.cpp -o arr Type ./arr	To comple type, g++ array.cpp -o arr To execute ./arr
	Here the output is displayed as, The sum is 6.
Summary	In this turoial we learnt, To add elements in a 2D array. To print 2D array. To calculate the sum of 2D array.
Assignment:	Write a program that takes two 2D arrays as input. Subtract them and find the result.
Slide 4 About the Spoken Tutorial Project Watch the video available at http://spoken-tutorial.org/What_is_a_Spoken_Tutorial It summarises the Spoken Tutorial project If you do not have good bandwidth, you can download and watch it	* Watch the video available at the following link It summarises the Spoken Tutorial project If you do not have good bandwidth, you can download and watch it
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	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
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	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 spoken hyphen tutorial dot org slash NMEICT hyphen Intro
Remain on previous slide No slide for this part	This is Ritwik Joshi from IIT Bombay. Thank you for joining.

Contributors and Content Editors

Ashwini