[C] Pointer to a string

Example1 :

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

int main()
{
    char s[] = "hello";
    /* tmp must allocate one memory store space. */
    char *tmp = malloc (20);
    char  *p;

    scanf("%s",tmp);
    p = strdup(tmp);
    printf("%s, %s\n", s, p);

}

Example2 :

#include <unistd.h>

int main(int argc, char *argv[])
{
    int option = -1;
    char *addr;
    char *port;

    while ((option = getopt (argc, argv, "i:p:")) != -1)
    {
         switch (option)
         {
         case 'i':
             addr = strdup(optarg);
             break;
         case 'p':
             /* This example show optarg already have store space. */
             port = strdup(optarg);
             break;
         default:
              /* unrecognised option ... add your error condition */
              break;
         }
    }

    printf("port = %s\n",port);

    return 0;
}

Show result

 $ ./a.out -p happy
port = happy

Reference:

• Can a pointer to a string be used in a printf?