passing *char parameters by reference

[Shiping Zhang]

In article <1424 at novavax.UUCP> gls at novavax.UUCP (Gary Schaps) writes:
>Would someone be kind enough to tell me why this program fails?
>
>char *x, *y;
>{
>   register char *temp;
>
>   temp = x;
>   x = y;
>   y = temp;
>}
>
>main()
>{
>   char *a="aaaa";
>   char *b="bbbb";
>
>   swap( &a, &b );
>   printf( " a = %s\t b = %s\n", a, b);
>}

The problem is the function swap. It should be defined as following:

swap(x,y)
char **x,**y; /* x and y are points to point to char */
{
    register char *temp;
    temp = *x; /* assign temp the address x points to */
    *x = *y;   /* make x point to the address y points to */
    *y = temp; /* reassign y the address x used to point to */
}


- ping