Difference between revisions of "C-and-C++/C3/Strings/English-timed"
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PoojaMoolya (Talk | contribs) (Created page with '{| border = 1 |'''Time''' |'''Narration''' |- | 00.01 |Welcome to the spoken-tutorial on Strings in C and C++ |- | 00.06 |In this tutorial we will learn, |- | 00.08 |Wha…') |
Kavita salve (Talk | contribs) |
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Revision as of 16:03, 18 March 2014
| Time | Narration
|
| 00.01 | Welcome to the spoken-tutorial on Strings in C and C++ |
| 00.06 | In this tutorial we will learn, |
| 00.08 | What is a string. |
| 00.10 | Declaration of a string. |
| 00.13 | Initialization of a string. |
| 00.15 | Few examples on string. |
| 00.17 | We will also see some common errors and their solutions. |
| 00.22 | To record this tutorial, I am using, |
| 00.25 | Ubuntu Operating System version 11.04 |
| 00.29 | gcc and g++ Compiler version 4.6.1 .
|
| 00.35 | Let us start with the introduction to strings. |
| 00.38 | String is a sequence of characters, that is treated as a single data item. |
| 00.44 | Size of string = length of string + 1
|
| 00.49 | Let me tell you how to declare a string. |
| 00.52 | The syntax for this is |
| 00.55 | char, name of string and size
|
| 00.59 | char is the data type, name of the string is the string name, and we can give the size here. |
| 01.06 | Eg: here we have declared a character string names with size 10 |
| 01.13 | Now we will see an example. |
| 01.15 | I have already typed the program, I will open it. |
| 01.19 | Note that our file name is string.c |
| 01.23 | In this program, we will take a string as an input from the user and print it.
|
| 01.29 | Let me explain the code now.
|
| 01.32 | These are our header files. |
| 01.34 | Here string.h includes the declarations, functions, constants of string handling utilities.
|
| 01.43 | Whenever we work on string functions, we should include this header file. |
| 01.47 | This is our main function. |
| 01.49 | Here we are declaring the string strname' with size '30'. |
| 01.55 | Here we are accepting a string from the user. |
| 01.58 | To read a string, we can use scanf() function with format specifier %s |
| 02.05 | We are using the caret sign and \n to include the spaces with the string. |
| 02.11 | Then we print the string.
|
| 02.13 | And this is our return statement.
|
| 02.16 | Now click on Save
|
| 02.18 | Let us execute the program. |
| 02.20 | Please open the terminal window by pressing Ctrl, Alt and T keys simultaneously on your keyboard.
|
| 02.30 | To compile, type gcc space string.c space -o space str |
| 02.37 | And press Enter
|
| 02.40 | To execute, type ./str
|
| 02.43 | now press Enter
|
| 02.46 | Here it is displayed as Enter the string . |
| 02.49 | I will type Talk To A Teacher. |
| 02.56 | now press Enter. |
| 02.58 | The output is displayed as The string is Talk To A Teacher |
| 03.03 | Now let us switch back to our slides
|
| 03.06 | Until now we discussed about the declaration of a string.
|
| 03.10 | Now we are going to discuss how to initialize the string. |
| 03.13 | The syntax for this is |
| 03.16 | char var_name[size] = “string”; |
| 03.20 | Eg: Here we have declared a character string "names" with size 10 and the string is "Priya" |
| 03.28 | Another syntax is |
| 03.31 | char var_name[ ] = String within single quotes
|
| 03.36 | eg: char names[10] = Priya in single quotes
|
| 03.42 | Let me show you how to use the first syntax with an example. |
| 03.48 | Switch back to our Editor. We will use the same example.
|
| 03.52 | First, press shift, ctrl and s keys simultaneously on your keyboard |
| 03.58 | Now save the file with the name stringinitialize |
| 04.03 | Now click on Save
|
| 04.06 | We are going to initialize the string.
|
| 04.08 | Hence, at the 5th line, type |
| 04.11 | = and within the double quotes “Spoken- Tutorial”;
|
| 04.20 | Now, click on Save
|
| 04.22 | Now remove these two lines, as we are only going to print the string. |
| 04.27 | Click on Save. |
| 04.30 | Let us execute.
|
| 04.31 | Come back to our terminal. |
| 04.33 | To compile, type
|
| 04.35 | gcc space stringinitialize.c space -o space str2
|
| 04.44 | Here we have str2 because we don't want to overwrite the output parameter str for the file string.c |
| 04.54 | Now press Enter. |
| 04.56 | To execute, type ./str2 |
| 05.00 | The output is displayed as "The string is Spoken-Tutorial". |
| 05.06 | Now we will see some common errors which we can come across . |
| 05.09 | Come back to our program
|
| 05.11 | Suppose here we type the spelling of string as sting
|
| 05.16 | Now click on Save.
|
| 05.18 | Let us execute |
| 05.19 | Come back to our terminal |
| 05.21 | Now compile as before |
| 05.23 | We see an fatal error.
|
| 05.25 | sting.h: no such file or directory
|
| 05.28 | compilation terminated
|
| 05.30 | Come back to our program. |
| 05.32 | This is because the compiler is not able to find the header file with the name sting.h
|
| 05.39 | Hence it is giving an error.
|
| 05.41 | Let us fix the error.
|
| 05.43 | Type r here.
|
| 05.45 | Now click on Save. |
| 05.46 | Let us execute again. |
| 05.47 | Come back to our terminal.
|
| 05.50 | Compile as before, execute as before. |
| 05.54 | Yes, it is working!
|
| 05.56 | Now, let us see another common error. |
| 05.59 | Come back to our program.
|
| 06.02 | Suppose, here, I will type int in place of char.
|
| 06.06 | Now, click on Save . |
| 06.07 | Let us see what happens.
|
| 06.09 | Come back to our terminal.
|
| 06.11 | Let me clear the prompt. |
| 06.15 | Compile as before. |
| 06.17 | We see an error. |
| 06.19 | Wide character array initialized from non-wide string
|
| 06.24 | format %s expects argument of type 'char, ' but argument 2 has type 'int'
|
| 06.32 | Come back to our program. |
| 06.36 | This is because we used %s as the format specifier for string. |
| 06.42 | And we are initializing it with an integer data type
|
| 06.47 | Let us fix the error. |
| 06.49 | Type char here.
|
| 06.51 | Click on Save. |
| 06.53 | Let us execute. Come back to our terminal. |
| 06.56 | Compile as before, execute as before.
|
| 07.00 | Yes it is working! |
| 07.03 | Now we will see how to execute the same program in C++ |
| 07.08 | Come back to our program.
|
| 07.11 | Let me open our file string.c |
| 07.15 | We will edit the code here.
|
| 07.18 | First, press shift, ctrl and S key simultaneously on your keyboard.
|
| 07.25 | Now save the file with an extension .cpp |
| 07.29 | and click on Save.
|
| 07.33 | Now we will change the header file as iostream. |
| 07.38 | Include the using statement. |
| 07.43 | Now click on Save.
|
| 07.47 | Now we will delete this declaration.
|
| 07.50 | And will declare a string variable. |
| 07.53 | Type string space strname and a semicolon |
| 07.59 | Click on Save.
|
| 08.02 | Replace the printf statement with the cout statement. |
| 08.07 | Delete the closing bracket here.
|
| 08.11 | Delete the scanf statement and type getline opening bracket closing bracket within the brackets type(cin, strname) |
| 08.24 | At the end, type a semicolon.
|
| 08.28 | Now again, replace the printf statement with the cout statement. |
| 08.36 | Delete the format specifier and \n
|
| 08.40 | Now delete the comma
|
| 08.42 | Type two opening angle brackets, delete the bracket here.
|
| 08.49 | Type two opening angle brackets and within the double quotes type \n
|
| 08.54 | And click on Save |
| 08.58 | Here we have declared a string variable 'strname' |
| 09.03 | Since we do not use the format specifier in C++, the compiler should know that strname is a string variable.
|
| 09.13 | Here we use getline to extract the characters from the input sequence.
|
| 09.18 | It stores them as a string.
|
| 09.22 | Now let us execute the program. Come back to our terminal.
|
| 09.27 | Let me clear the prompt. |
| 09.30 | To compile, type |
| 09.32 | g++ space string.cpp space -o space str3
|
| 09.39 | and press Enter.
|
| 09.41 | To execute, type ./str3
|
| 09.46 | Press Enter.
|
| 09.47 | It is displayed as Enter the string |
| 09.50 | I will enter as Talk To A Teacher
|
| 09.55 | Now press Enter |
| 09.57 | The output is displayed as |
| 09.59 | "The string is Talk To A Teacher"
|
| 10.03 | We can see that the output is similar to our C code. |
| 10.07 | Now come back to our slides.
|
| 10.10 | Let us summarize |
| 10.11 | In this tutorial we learnt
|
| 10.13 | Strings
|
| 10.14 | Declaration of a string
|
| 10.16 | eg: char strname[30] |
| 10.20 | Initialization of a string
|
| 10.21 | eg: char strname[30] = “Talk To A Teacher” |
| 10.26 | As an assignment |
| 10.28 | Write a program to print a string using the 2nd syntax |
| 10.34 | Watch the video available at the link shown below |
| 10.37 | It summarizes the Spoken Tutorial project |
| 10.40 | If you do not have good bandwidth, you can download and watch it |
| 10.44 | The Spoken Tutorial Project Team |
| 10.46 | Conducts workshops using spoken tutorials |
| 10.49 | Gives certificates to those who pass an online test |
| 10.54 | For more details, please write to, contact@spoken-tutorial.org |
| 11.01 | Spoken Tutorial Project is a part of Talk to a Teacher project |
| 11.04 | It is supported by the National Mission on Education through ICT, MHRD, Government of India
|
| 11.12 | More information on this Mission is available at the link shown below |
| 11.16 | This is Ashwini Patil from IIT Bombay signing off. |
| 11.20 | Thank You for watching. |
