void fun (char *s, char *t1, char *t2 , char *w)
{
char *p , *r, *a;
strcpy( w, s );
while ( *w )
{ p = w; r = t1;
while ( *r )
if ( *r == *p )
{ r++; p++; }
else break; /*就是这个break,是跳出while(*r)还是while(*w)?*/
if ( *r == '\0' ) a = w;
w++;
}
r = t2;
while ( *r ){ *a = *r; a++; r++; }
}