Thread: Using Strings with Functions

First of all, main always returns an int so it is" int main()" NOT "void main()"!!

Second, I am unfamiliar with the calling convention "dest = *noblank...." so I will address this ignoring that.

There are two approaches you might try: pass the destination string as a parameter to noblank, or just change the original string within the function and return it in it's changed form. I'll illustrate the second method:

#include <stdio.h>
#include <string.h>


void noblank(char *);

int main ()
{

char sentence[81];
int i, length;

printf("enter a sentence> \n");

fgets(sentence, 80,stdin);

noblank(sentence); // or even "noblank(&sentence[0]);"

printf("%s\n", sentence);
}





void noblank(char *string)

{
int i,j=0;
int newlen = strlen(string)+1;
char temp[newlen];
for (i = 0; i != ' ' && i != '\n' && i < newlen; ++i)
{
temp[j] = string[i];
j++;
}
strcpy(string,temp);
}


__________________

I also noticed you try to access "length" within the function. Don't do that because 1)length is not global 2)length should not be global anyway 3)You add an unnecessary parameter to your function when the function can just as well find the length of "sentence".

Ok, fine - you reply while I think about it

So now I can fix yours instead

> First of all, main always returns an int
So do it - don't just say it.
Your example shuffles uneasly off the end of the function.

> fgets(sentence, 80,stdin);
Why the size difference?
fgets ( sentence, sizeof(sentence), stdin );
works just as well, and you don't have to think "now does this allow for \0 or not".

> char temp[newlen];
This isn't even valid 'C' - you can't declare arrays with variable length. To do this, you would need to call malloc.

The important thing to realise about this problem is that the new string can never be longer that the old string, so I would think it would be ok to re-use it in place.

Code:

#include <stdio.h>

void noblank(char *string) { 
    int i, j;
    for ( i = 0, j = 0 ; string[i] != '\0' ; i++ ) {
        if ( string[i] != ' ' ) string[j++] = string[i];
    }
    string[j] = '\0';
}

int main ( ) {
    char    test[] = "hello world";
    noblank( test );
    printf( "%s\n", test );    
    return 0;
}

OK smartypants!

> First of all, main always returns an int
>So do it - don't just say it.
>Your example shuffles uneasly off the end of the function.

Simple Typo...

> fgets(sentence, 80,stdin);
>Why the size difference?
>fgets ( sentence, sizeof(sentence), stdin );
>works just as well, and you don't have to think "now does this >allow for \0 or not".

If the string is 80 in length, that means 79 chars and a '\0' right?
So if fgets is recieving input from a user who enters 99 chars, it gets 80 of those and no room for the null terminator, right?


> char temp[newlen];
>This isn't even valid 'C' - you can't declare arrays with variable >length. To do this, you would need to call malloc.

Not true, I have used this convention hundreds of times! Perhaps I have a "smart" compiler, Salem!

*grumble*

I must add that your convention of using the same string is quite ingenious, Salem. Kudos!

i DON'T INDERSTAND THAT WHAT IS meant by "blank".
are u talking about spaces that we use to seperate one word to another? that means the ascii code of that is 32. m i right?

> are u talking about spaces that we use to seperate one word to another?
Yes
Though blanks can also include tabs and newlines.

> that means the ascii code of that is 32
That's the one.

Then we should not use only "isspace" function. we should consider if there is any spaces or tabs or any newlines.
all of the conditions should be checked.
....how a user can add a new line to a string if he/she is asked to enter a string?