Advance-C/C2/Command-line-arguments-in-C/English
Title of script: Command Line Arguments
Author: Ashwini Patil
Keywords: Video tutorial, Command Line Arguments, main()
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| Display Slide | Hello and welcome to the spoken tutorial on Command Line Arguments. |
| Display Slide | In this tutorial, we will learn about
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System Requirements |
For this tutorial I am using
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Prerequisites
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To follow this tutorial you should be familiar with C tutorials.
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| Show the pointer to | Let us start with our program.
I have a code file. I will open it. Filename is main-with-args.c |
| Let me explain the program.
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| #include <stdio.h>
#include <stdlib.h> |
These are the header files.
stdio.h defines core input and output functions. stdlib.h header file defines,
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| int main(int argc, char **argv) | This is our main function.
Inside this we have passed two arguments. int argc, char **argv |
| int main(int argc, char **argv) | “argc” refers to the number of command line arguments passed to the program.
This includes the actual name of the program. |
| Argv contains actual arguments.
Starting from index 0. Index 0 is the name of the program. Index 1 will be the first argument passed to the program. Index 2 will be the second argument passed to the program. And so on. | |
| printf("argc is %d\n",argc); | This statement will display the total number of arguments passed to the program. |
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printf("argv is %s\n",argv[1]); |
This will display the 1st argument passed to the program.
1 represents the argument at index 1. |
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while(argc--) |
While condition will decrement the number of arguments. |
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printf("arguments are %s\n", *argv++); |
This statement will print all the arguments passed to the program. |
| return 0; | At the end we have return 0 statement. |
| Press Ctrl+Alt+T | Let us open the terminal by pressing Ctrl+Alt+T keys.
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| Compile
Type: gcc main-with-args.c -o args |
Type: gcc main-with-args.c -o args
Press Enter |
| Execute | Type: ./args
Press Enter |
| Point to the output on the Terminal | You can see the output as:
Total number of arguments are 1 The first argument is (null) arguments are ./args |
| Command line arguments are given during execution.
Total number of arguments are 1 as the zeroth argument is the executable filename itself. The first argument is (null) as we have not passed any argument to the program. Arguments are only one ie. ./args | |
| Highlight:
Type: ./arg.sh Sunday Monday Tuesday
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Now let us execute again
Press the uparrow key space Monday space Tuesday Press Enter |
| (change in your program also) | Now we can see the output as:
Total number of arguments are 4 The first argument is Sunday Argument is ./args Argument is Sunday Argument is Monday Argument is Tuesday |
| Let me explain the output. | |
| Output:
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Total number of arguments are 4 as ./args, Sunday, Monday and Tuesday.
The first argument is Sunday The zeroth argument always gives “executable filename” Sunday is assigned to first argument . Monday is assigned to second argument. Tuesday is assigned to third argument
Let us summarize. |
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Summary |
In this tutorial we learnt,
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| Assignment | As an assignment,
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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 |
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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 |
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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 |
| This is Ashwini Patil from IIT Bombay signning off.
Thank you for joining. |
