char buffer[1024]
char *p = buffer + 512;

char buffer[1024];
char *p = &buffer[512];

char buffer[1024];
strcpy(buffer, "hello ");
strcpy(buffer + 6, "world!");

char buffer[1024];
strcpy(buffer, "hello ");
strcpy(&buffer[6], "world!");

char *my_strcpy(const char *s, char *t) {
  char *u = t;
  while (*t++ = *s++);
  return u;
}

#include ctype.h
void skip_spaces( const char **ppsz )
{
  const char *psz = *ppsz;
  while( isspace(*psz) )
    psz++;
  *ppsz = psz;
}

void fn(void)
{
  char a[]="  Hello World!";
  const char *psz = a;
  skip_spaces( &psz );
  printf("n%s", psz);
}