C Programming - Command Line Arguments - Discussion

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"Two things are infinite: the universe and human stupidity; and I'm not sure about the universe."

- Albert Einstein

If the different command line arguments are supplied at different times would the output of the following program change?

#include<stdio.h>

int main(int argc, char **argv)
{
    printf("%d\n", argv[argc]);
    return 0;
}

[A].

Yes

[B].

Answer: Option D

Explanation:

No answer description available for this question.

Deepika said: (Fri, Oct 22, 2010 09:58:21 AM)

Anyone please help me. How is it works?

Sundar said: (Fri, Oct 22, 2010 11:04:31 AM)

@Deepika: agrc - It is an integer value contains the number of arguments passed to main function through command line. Lets assume argc = 3. The 3 arguments will be stored in the two dimensional array argv as given below. argv[0] = 1st argument value argv[1] = 2nd argument value argv[2] = 3rd argument value. But in the given program, it is mentioned like argv[argc] it means that argv[3]. This array holds the values upto argv[2] only (argv[0] - argv[2]). Therefore, argv[3] may be contain null value or garbage value. While converting this value as integer (because in printf statement "%d" specified), it will give 0 as output. Therefore, the program's output will NOT change due to the number of arguments passed. Note: If you use %s instead of %d in the printf statement, it may print (null) or any garbage value depends upon the platform. There is a chance for abnormal program termination too. Hope this will help you. Have a nice day!

Karthi said: (Tue, Mar 1, 2011 01:40:45 PM)

Thank you somuch sundar. Its clear now.

Arun said: (Wed, Aug 3, 2011 01:48:17 PM)

Good explanation sundar keep going.

Subhendu Bera said: (Wed, Aug 22, 2012 07:18:19 PM)

According to the C standard 2011 section 5.1.2.2.1 paragraph "argv[argc] shall be a null pointer." If it is printed using %d then it will print 0. @sundar your statement "Therefore, argv[3] may() be contain null value or garbage value()....." is wrong it will only contain null value. There is no scope of garbage and it is irrespective of compiler. If it "may be" null or gurbage then output would vary with every execution.

Ramakri said: (Tue, Dec 4, 2012 12:14:14 PM)

Is ** argv is same as argv[]? usually we use, int main(int argc, char argv[]);