chalanging programing to solve

ok i wanted to enter a surname that can only fits 20 character...
but if some one enters more then 20 character, it would just read the first 20 character that is written, when it is printed out...but the character after the 20th one, will not be written anywhere and as a matter of fact, i don't want it to affect the rest of the program...

this is what i have so far...

Code:

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#include <stdio.h>

int main(int argc, char ** argv)
{
// Mainline Variable Declarations
FILE * output = stdout;
FILE * input = stdin;

char * LName[20];

                        {
                        //Enter last name
                        fprintf(output,"--------------------------\n"); fflush(output);
                        fprintf(output,"Enter Your last name(maximum of 20 letters): "); fflush(output);

                        //input last name
                        fscanf(input,"%20s%*c",&LName);fflush(output);
                        }
//output

        fprintf(output," %s",LName);

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"LName" is an array of pointers to characters, not an array of characters. So that's all wrong. Other than that, you'll need 21 characters in your array, so that you can truncate the string with the null character. Finally, you'll have to decide what it is you want to do to handle extra input. Probably you can get away with just reading and discarding everything past the 20th character, until you hit a newline character.

Is there any particular reason you're aliasing stdin and stdout?


Quzah.

Quote:

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Originally Posted by quzah

"
Is there any particular reason you're aliasing stdin and stdout?
Quzah.

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yeah there is a reason, its part of the thing i have to do...
so yeahh...
but i don't really understand what you mean..can you explain in more detail...
thank you

You might want to look at C String tutorial first, then you'll know the difference between "char var[]", "char *var" and "char *var[]".

There's also an example that uses fgets() to read a string of maximal size 256, you can easily modify it to read only 20 characters.

Quote:

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Originally Posted by KONI

You might want to look at C String tutorial first, then you'll know the difference between "char var[]", "char *var" and "char *var[]".

There's also an example that uses fgets() to read a string of maximal size 256, you can easily modify it to read only 20 characters.

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i know the difference between "char var[]" "char *var" and "char *var[]"
and have tried fgets, but it stills deosn't work, and plus i m not suppose to use that...

Quote:

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Originally Posted by j4k50n

and have tried fgets, but it stills deosn't work, and plus i m not suppose to use that...

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How are we supposed to help you if you make us play 20 questions?

fgets() would be the perfect way of doing it otherwise.

> i know the difference between "char var[]" "char *var" and "char *var[]"
Doesn't look like it from where I'm sitting.

> fscanf(input,"%20s%*c",&LName);
To make this work, you would need

char LName[21];
fscanf(input,"%20s%*c",LName);

Which would read
- upto (and including 20 character)
- upto (and excluding) the first white-space character

The %*c reads (and throws away) the next character (only).

Now what happens next depends entirely on the format of your text file. Any random white space for example in the text file can seriously affect how robust your use of fscanf is.

Quote:

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Originally Posted by Salem

>
The %*c reads (and throws away) the next character (only).

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yeah i put that in because it also reads out the enter button when i press enter, so its suppose to read enter button and erase it..

Quote:

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Originally Posted by j4k50n

... its suppose to read enter button and erase it..

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get away from my keyboard !