bn_ptr drive_temp(bn_ptr head,bn_ptr temp,bn_ptr current) { while(temp->next!=current) { temp=temp->next; current=temp; } temp=head; return current; } I have linked list and 'head' pointer hold first node , 'current' pointer hold last node,I want to bring 'current' to head one by one ,so I write this function but it gives segmentation fault when I debug the program
temp->next!=current will never be true unless temp==temp->next.
Try this:
bn_ptr drive_temp(bn_ptr head,bn_ptr temp,bn_ptr current) { while(temp->next!=current) { temp=temp->next; } current=temp; /* get this out of the loop */ temp=head; return current; } or more simplified this:
bn_ptr drive_temp(bn_ptr head,bn_ptr temp,bn_ptr current) { (void)head; /* head isn't used, so put this to avoid warning */ while(temp->next!=current) { temp=temp->next; } /* current and temp will be lost, so assigning to them here is useless */ return temp; } To make it safer, make sure that temp isn't NULL to avoid runtime error in case of current is invalid.
bn_ptr drive_temp(bn_ptr head,bn_ptr temp,bn_ptr current) { (void)head; /* head isn't used, so put this to avoid warning */ while(temp != NULL && temp->next!=current) { temp=temp->next; } /* temp will be the previous node of current or NULL */ return temp; } Maybe you want this:
bn_ptr drive_temp(bn_ptr head,bn_ptr current) /* remove temp from the arguments */ { bn_ptr temp = head; while(temp != NULL && temp->next!=current) { temp=temp->next; } /* temp will be the previous node of current or NULL */ return temp; }