C-and-C++/C3/Arrays/English

Title of script: Arryas in C and C++

Author: Ashwini Patil

Keywords: arrays, single dimensional, multi dimensional, video tutorial()

Visual Cue	Narration
Slide 1	Welcome to the spoken-tutorial on Arrays in C and C++.
Slide 2	In this tutorial we will learn, What is an array. Declaration of an array. Initialization of an array. Few examples on array. We will also see some common errors and their solutions.
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 4-5	Let us start with the introduction to Array. Array is the collection of data or elements of same data-type. Array index starts from 0. The first element is stored at index 0. There are three types of arrays: Single dimensional array. Two dimensional array. Multi-dimensional array. We will be discussing single dimensional array in this tutorial.
Slide 6	Let us see how to declare a single dimensional array. The Syntax for this is: data-type (name of the array) and size; eg.( char star[5];) Here we have declared an integer array star which contains 5 elements. The array index will start from star0 to star 4.
Slide 7	We saw the declaration of an array now we will see the initialize of an array. The Syntax for this is: data-type (name of the array)array-name[size]={elements}; eg. int star[3]={1,2,3}; Here we have declared an integer element star with size 3. The elements of the array are 1, 2 and 3. Here the index will start from star0 to star 2.
On the editor	Now let us move to the examples. I have already typed the program on the editor. So, let me open it.
Point to array.c	Please note that our file name is array.c
	In this program, we will calculate the sum of the elements stored in an array. Let me explain the code now.
Highlight #include <stdio.h>	This is our header file.
Highlight int main()	This is our main function.
Highlight int star[3]={1,2,3};	Here, we have declared and initialized an array star with size 3. The elements of the array are 4, 5 and 6.
Highlight int sum;	Then we have declared an integer variable sum.
Highlight sum = star[0] + star[1] + star[2];	Here we add the elements of the array and store the result in sum. Note that 4 will be stored at index 0. 5 will be stored at index 1 and 6 will be stored at index 2.
Highlight printf("The sum is %d\n",sum);	Then we print the sum.
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 your keyboard.
On the terminal Type gcc array.c -o array ./arr	To compile type, gcc space array.c space -o space array Press Enter To execute type, ./array Press Enter
Highlight Output	Here the output is displayed as, The sum is 15.
Errors	Now let us see some common errors which we can come accross.
On the editor	Come back to our program.
Delete {} int star[3]=1,2,3;	Suppose here at line no.4, we miss the curly brackets.
Click on Save	Click on Save.
	Let us see what happens.
On the terminal	Come back to our terminal. Let us compile as before.
Highlight Error	We see errors. Invalid initializer and Expected identifier or (bracket) '(' before numeric constants.
{ }	This is because arrays must be initialized within curly brackets.
	Come back to our program. Let us fix the error. Type the curly bracket here at line no. 4. Now click on Save
	Let us execute. Come back to our terminal. Let us compile as before. Let us execute as before. Yes it is working.
	Now we will execute the same program in C++.
On the editor	Come back to our program.
	I will change a few things here.
Now save the file with an extension .cpp	First press shift+ctrl and s keys simultaneously on your keyboard. And click on Save
Type iostream	Let us change the header file as iostream.
Type using namespace std;	Now include the using statement. The declaration and initialization of an array is same in C++. Hence no need to change anything here.
Type cout <<	Now replace the printf statement with the cout statement.
Delete	Delete the format specifier and backslash n. Now delete the comma and type two opening angle brackets. Delete the bracket here. Again type two opening angle brackets and within the double quotes type backslash n.
Click on Save	Now click on Save
	Let us execute.
On the terminal	Come back to our terminal
Type g++ array.cpp -o arr Type ./arr	To compile type, g++ space array.cpp space -o space array1 Here we have array1 because we don't want to overwrite the output parameter array for the file array.c Now press Enter To execute ./array1 press Enter
Highlight Output	The output is displayed as, The sum is 15. We can see that it is similar to our C code.
Errors	Now we will see another common error Come back to our program.
At line 7 Type: star[1] + star[2] + star[3];	Suppose here, at line number 7 I will type star[1] + star[2] + star[3]; Click on Save
On the terminal	Let us execute. Come back to our terminal. Let me clear the prompt.
	Let us compile as before. Let us execute as before.
Highlight Output	We get an unexpected output. This is because array index starts from 0.
Highlight star[1]	Come back to our program. We can see here the array index starts from 1. Hence it is giving an error.
Summary	Let us fix the error. Type 0 here 1 and 2. Click on Save
Summary	Let us execute. Come back to our terminal. Let us compile as before. execute as before. Yes it is working. Now we will go back to our slides.
Summary	Let us summarise. In this tutorial we learned, Arrays. To declare Single Dimensional Array. To initialize Single Dimensional Array. eg. int star[3]={4,5,6} To add the elements of an array. eg. sum = star[0] + star[1] + star[2];
Assignment	As an assignment, Write a program to calculate the difference of the elements stored in an array.
Slide 11 http://spoken-tutorial.org /What\_is\_a\_Spoken\_Tutorial About the Spoken Tutorial Project	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
Slide 12 Spoken Tutorial Workshops	The Spoken Tutorial Project Team Conducts workshops using spoken tutorials Gives certificates to those who pass an online test For more details, please write to contact@spoken-tutorial.org
Slide 13 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 the link shown below: http://spoken-tutorial.org\NMEICT-Intro
	Ashwini Patil from IIT Bombay Thank You for joining

Contributors and Content Editors

Ashwini