C language A code example for solving the problem of reverse order of strings and one-way list _c language

String reverse
The last interview encountered a one-way list of the reverse sequence of the topic, fortunately the string reverse order more familiar with the analogy made. String reverse order is simpler, directly on the code:

void Stringreverse (char* p1,char* p2) 
{ 
 if (P1==P2) return; 
 Swap the value of P1, p2 
 *p1= (*P1) + (*P2); 
 *p2= (*P1)-(*P2); 
 *p1= (*P1)-(*P2); 
  if (p1==p2-1) return; 
  else Stringreverse (++p1,--p2); 
} 

Call Example:

Stringreverse (Str,str+strlen (str)-1); 

Reverse order of one-way linked list
first three pictures: The original state is figure one, all the reverse order is the appearance of Tu San, figure II is a reverse step after the appearance. Follow the steps in Figure two to move one step at a time, and reverse the p1->next until all is reversed. Detailed principle see code.
Figure I:

Figure II:

Figure III:

typedef struct node node; 
struct node{ 
 int data; 
 Node* Next; 
 
node* reverselinklist (node* head) { 
 if (head==null| | Head->next==null) {return head 
  ; 
 } 
 node* P1 = head; 
 node* P2 = p1->next; 
 node* P3 = p2->next; 
 P1->next = Null;//p1 to end pointer, so point to NULL while 
 (p3!=null) { 
  p2->next = p1;//p2->next reverse 
  p1=p2;// P1 pointer moves backward p2=p3;//p2 pointer moves back one step 
  p3=p3->next;//p3 pointer moves backward 
 p2->next=p1;//p3 points to null, P2 
 the reverse head=p2;//header pointer to the previous tail pointer return head 
 ; 
} 

It's over.