unknown escape sequence:

[h4ever]

How to correct this error?
args.c|35|warning: unknown escape sequence: '\-' [enabled by default]|

char helpStr[] = {"Usage:\n\t-h\t Displays this help message\n\t\-i\tThe name of the input image for blurring\n\
\t-g\tThe size of the gaussian kernel. Default is 3\n\
\t-s\tThe sigma parameter of the gaussian. Default is 0.8\n\
"};

gcc

BTW: Does the forum have any kind of poping ad window? I cannot close it, having avira installed, not sure is it adware or cplusplus.com ad.

[Peter87]

The backslash is used for escape characters so you need to escape backslash itself if you want it in a string literal.

char helpStr[] = {"Usage:\\n\\t-h\\t Displays this ... 

[giblit]

@Peter I think they are trying to have a menu that looks something like

Usage:
    -h    Displays this help message
    -i    The name of the input for blurring
    -g    The size of the gaussin kernel. Default is 3
    -s    The signma parameter of the gaussian. Default is 0.8

\-i This is supposed to be -i

*had a typo

[h4ever]

I dont think the point of the text is to display \n and \t, this should be used to generated linebreak and tab in text. But when I try to remove the backslashes on the end of lines:

char helpStr[] = {"Usage:\n\t-h\t Displays this help message\n\t\-i\tThe name of the input image for blurring\n
\t-g\tThe size of the gaussian kernel. Default is 3\n
\t-s\tThe sigma parameter of the gaussian. Default is 0.8\n
"};

so I got error missing terminating character ".

So just tell me how to separate the text on more lines if is it possible.

[giblit]

You also have a few other stray ones. Usage:\n\t-h\t Displays this help message\n\t\-i\tThe name of the input image for blurring\n\
\t-g\tThe size of the gaussian kernel. Default is 3\n\
\t-s\tThe sigma parameter of the gaussian. Default is 0.8\n\


Edit I see you found 3 of the 4.

By the way I don't think it wil compile to start each line put a " before and and " at the end. like

char helpStr[] = {"Usage:\n\t-h\t Displays this help message\n\t-i\tThe name of the input image for blurring\n"
"\t-g\tThe size of the gaussian kernel. Default is 3\n"
"\t-s\tThe sigma parameter of the gaussian. Default is 0.8\n"};

[h4ever]

But it's not clear to me how to break the text in the code, for the line not to be too long.

[ne555]

"help message\n\t\-i\tThe name of"
note that you have written '\-' which is not a valid escape sequence
drop the backlash.


Also, to improve readability you may want to use raw string literals

char help[] =
R"(Usage:
	-h	Displays this help message
	-i	The name of the input image for blurring
	-g	The size of the gaussian kernel. Default is 3
	-s	The sigma parameter of the gaussian. Default is 0.8
)";

edit: scratch that, you are using C

[h4ever]

nothing works

[JLBorges]

#include  <stdio.h>

int main()
{
    const char helpStr[] = "Usage:\n\t-h\tDisplays this help message\n\t-i\tThe name of the input image for blurring"
                           "\n\t-g\tThe size of the gaussian kernel. Default is 3\n\t-s\tThe sigma parameter of the "
                           "gaussian. Default is 0.8\n" ;
    puts(helpStr) ;
}

http://rextester.com/HDJNN12526

[h4ever]

Thank you

[JLBorges]

Ok, now that we have realised that adjacent string literals are concatenated, let us make the code more readable (and maintainable):

#include  <stdio.h>

int main()
{
    const char helpStr[] = "Usage:\n"
                           "        -h    Displays this help message\n"
                           "        -i    The name of the input image for blurring\n"
                           "        -g    The size of the gaussian kernel. Default is 3\n"
                           "        -s    The sigma parameter of the gaussian. Default is 0.8\n" ;
    puts(helpStr) ;
}

http://rextester.com/XXPB22600