Programming

i have a function that's parameter is char *s

and in the main function i am sending that function &(argv[1]), but i dont think this is working, how can i fix this?

can i cast it to be a string or something?

is there a way i can create a new string thats exactly what argv[1] is equal to without specifying how long it is?

The parameter you have to use is simply argv[1], not &(argv[1]) .

argv[1] is just a pointer, and so it can be a char* .

Code:

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

int main(int argc, char **argv)
{
    char *str = (char *)NULL;
    int len = 0;

    if (argc != 2) return 1;

    len = strlen(argv[1]);
    printf("Length of argv[1] = %d\n", len);

    if ((str = malloc(len + 1)) != NULL) {
       bzero(str, len + 1);
       strncpy(str, argv[1], len);
       printf("argv[1] = %s\n", str);
    }

    free(str);

    return 0;
}

A few things to consider.

The comment regarding trying to free memory is patently incorrect as I specifically handled that case with

Code:

char *str = (char *)NULL;

The long starting practice since the dawn of the C language is that if the argument to free() is a null pointer, no action shall occur. This was and is codified by all versions of the various C standards.

As regards the comment that bzero() is deprecated, yes it is deprecated on some platforms and in some standards and specifications but is not depreciated in others. I did not claim any particular conformance so the comment lacks standing.

Patently? Perhaps, if I understand you correctly. Incorrect? Too absolute for the case. Rather redundant, and most likely unnecessary like your use of bzero() in this case. Or the casting of the NULL for the same matter.

Of course, as you, I must make emphasis of what I did not "claim": I did not claim to be correct, nor did I wrote any comment or addition as a vehicle for your personal engagement.
At the risk of stating the obvious, at the top of the quote I wrote. A few things to consider. You take it or leave it, writing generally, that is.


While I never said "depreciated", and the emphasis was more in the question mark, the stated "lacking of standing", I leave it unchallenged for others to judge and make their own opinion, if any.

As for more information, to whoever has interest, bzero() is part of the Berkeley UNIX C library, and memset() is part of the AT&T UNIX C library. The C Standard Library favored memset() and adopted it, and bzero() became deprecated. The use of the latest, is discouraged in favor of portability.

Code:

#include <stdio.h>
#include <strings.h>
#include <stdlib.h>

int main(int argc, char **argv)
{
    char *str;
    if((argc>=2)&&(str=strdup(argv[1])))
    {
            printf("argv[1] = %s\n", str);
            free(str);
            return 0;
    }
    else
    {
        return 1;
    }
}