Thread: string arrays

>What does it serve to place a "*" before a function name.

It declares the function to be returning a pointer of some type. The function strcat returns a pointer to char.

>Furthermore, what does "const" before char *s2 mean? Am i right to say it means what ever string s2 is pointed to cannot be change. It must remain constant.

Yes. The prototype makes a promise to you, the caller, that the function will not modify what is pointed to by s2.

>what is the difference between static and global variables?

Does this help?

>What difference will it be if it is declared in a function definition? Am i able use the value of that static variable in other functions other rather the one it is declared in?

No.

Code:

int *ptr;
ptr = strcat(s1,s2);

You want ptr to be of type char* since that is what strcat returns.

Code:

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

int main(void)
{
   char s1[20] = "hello";
   char s2[]   = " world";
   char *ptr;
   ptr = strcat(s1,s2);
   puts(ptr);
   return(0);
}

/* my output
hello world
*/

>can i just use
> return 0;
>?

Yes.

Hmmm. I must've copied that part of the code from somewhere else. I used to always parenthesize return values, but I moved away from that style a while ago.

Originally posted by Dave_Sinkula
>What difference will it be if it is declared in a function definition? Am i able use the value of that static variable in other functions other rather the one it is declared in?

No.

What? What are you talking about? What would be the point of returning static variables if you couldn't use them in other functions? Of course you can use them in other functions.

Code:

char *foo( void )
{
    static char buf[1024];

    if( buf[0] )
        printf( "%s\n", buf );

    memset( buf, 0, 1024 );

    return buf;
}

int main( void )
{
    char *ptr;

    ptr = foo( );

	*ptr++ = 'S';
	*ptr++ = 'e';
	*ptr++ = 'e';
	*ptr++ = '?';

    foo( );
    return 0;
}

Quzah.

>What are you talking about?

Declaring static variables globally mean it can only be used in that file only. What difference will it be if it is declared in a function definition? Am i able use the value of that static variable in other functions other rather the one it is declared in?

Since it was referred to in the context of a comparison to symbols with file scope, I assumed Raison meant referencing a symbol outside of the block scope in which it was declared static.

Code:

int main( void )
{
   strcpy(buf, "See?"); /* Error: Undefined symbol 'buf' in function main */
   return 0;
}

>>Am i able use the value

But I guess that's not what was asked.

Originally posted by Dave_Sinkula
Since it was referred to in the context of a comparison to symbols with file scope, I assumed Raison meant referencing a symbol outside of the block scope in which it was declared static.

Ah gotcha. Totally see where you were coming from, and in that way you're 100% correct. 'static' doesn't make them like globals, unless you happen to be using static globals.

Quzah.

Hey Hammer,
I'm sorry if i have offended you or anyhting or anyone. I don't know much about c programming, ,but i believe getting help and directions from people who know would help me get there.
If you can't help it's ok, but someone might be interested in helping. We've all been in situations sometime!
Thanks.