Scaning chars while initializing program?

This is a discussion on Scaning chars while initializing program? within the C Programming forums, part of the General Programming Boards category; Hello. I was wondering if anyone knew how to scan in a string if you place it right after how ...

  1. #1
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    Scaning chars while initializing program?

    Hello. I was wondering if anyone knew how to scan in a string if you place it right after how to initiate the program.
    i.e. a.out ContentsOfString

    and also if anyone could help out... i need to scan the line below it into a string also.
    so...

    a.out ContentsOfString
    String2contets

    any advice could help.

    Thanks, Curtis

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    Is your requirement parsing the command line arguments?

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    Re: Scaning chars while initializing program?

    Tell me your requirement or problem clearly.
    whether you want to parse a command line argument or read the string before initialize the program(Like configuration )
    or do you want to read a line

    If you want to get a arguments you can use argv in the main function
    int main(int argc,char **argv)
    Last edited by sganesh; 03-02-2010 at 02:24 AM.

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    i need to be able to save both the strings to use them in a cypher. But i also must run the program as
    $ a.out key <---The key used for the cypher

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    The following program is reading the keys passed to the program and print them.For example,I simply printed the arguments.If you have any argument,you use those strings in your cypher.

    Code:
    #include	<stdio.h>
    	int
    main ( int argc, char *argv[] )
    {
    	int i=0;
    	if(argc==1)
    		printf ( "Please Enter the Command line arguments\n"  );
    	else
    	{
    		for(i=1;i<argc;i++)
    			printf ( "Arguments Passed Are:%s\n", argv[i] );
    	}
    	return 0;
    }

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    Creedy, the C program can be passed, at start up, many parameters - that's just no problem at all.

    They are loaded into a char array with multiple rows, with one row for each word.

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    I guess you wanna give a string with multiple lines in a command line argument and parsing it ?
    If yes
    give the string in a command line enclosed in ""
    $ a.out string1 "string2
    continuation of string 2
    ....... etc "

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    Thank you vivekraj, Adak, and Alexander jack. I understand it better now, it all just came together. I think i should be able to finish the program now. Thanks.

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    Dangit. One more issue. If i want the first letter of the key then i would printf argv[ i ][ 0 ] ?

  10. #10
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    Yes.
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    Look up a C++ Reference and learn How To Ask Questions The Smart Way

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    when i try to print it i get an error:
    format ‘%s’ expects type ‘char *’, but argument 2 has type ‘int’

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    While printing the first character alone use %c instead of %s

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    Code:
                            printf ( "First char :%c\n", argv[i][0] );

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    Okay cool. Thanks everyone.

  15. #15
    C++ Witch laserlight's Avatar
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    By the way, a command line argument might be a zero length string, which means that argv[i][0] for that command line argument would be a null character. I am not entirely sure how that factors in when you are trying to print it.
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