#include

#include

#define ElemType int

typedef struct{

ElemType e;

struct Node *next;

}Node,*pNode,**ppNode;//使用pNode表示一级指针,ppNode表示二级指针

//计算整数n的m次方

int pow2(int n,int m);

int getElemNum(pNode head);

pNode getLastElem(pNode head);

void push(ppNode head,ElemType e);

ElemType pop(ppNode head);

void showElem(pNode head);

pNode getElem(pNode head,int i);

int main(int argc, char *argv[])

{

printf("%d\n",changto2(10));

printf("%d\n",changto10(1010));

return 0;

}

int changto2(int n){

if(n<0) return -1;

if(n==0) return 0;

int i,j,k,sum=0;

pNode head=NULL;

while(n!=0){

i=n%2;

n=(n-i)/2;

push(&head,i);

}

k=getElemNum(head);

for(j=k;j>0;j--){

int t = pop(&head);

int x = pow2(10,j-1);

sum=t*x+sum;

}

return sum;

}

int pow2(int n,int m){

int sum=1,i=0;

for(i=0;i

sum=sum*n;

}

return sum;

}

int changto10(int n){

if(n<0) return -1;

if(n==0) return 0;

int i,j,k,sum=0;

pNode head=NULL;

while(n!=0){

i=n%10;

n=n/10;

push(&head,i);

}

k=getElemNum(head);

for(j=k;j>0;j--){

int t = pop(&head);

int x = pow2(2,j-1);

sum=t*x+sum;

}

return sum;

}

int getElemNum(pNode head){

if(!head) return 0;

pNode p=head;

int i=0;

while(p){

i++;

p=p->next;

}

return i;

}

pNode getLastElem(pNode head){

if(!head) return NULL;

pNode p=head;

while(p->next) p=p->next;

return p;

}

void push(ppNode head,ElemType e){

pNode node = (pNode)malloc(sizeof(Node));

node->e=e;

node->next=NULL;

if(!*head){

*head=node;

return;

}

pNode p;

p=getLastElem(*head);

p->next=node;

}

ElemType pop(ppNode head){

int n =getElemNum(*head);

ElemType e;

if(n<1) return;

if(n==1){

e=(*head)->e;

free(*head);

*head=NULL;

return e;

}

pNode p = getElem(*head,n-1);

pNode t=p->next;

e=t->e;

free(p->next);

p->next=NULL;

return e;

}

pNode getElem(pNode head,int i){

int n = getElemNum(head);

if(i<1 || i>n) return;

int j=1;

pNode p=head;

while(j

j++;

p=p->next;

}

return p;

}

void showElem(pNode head){

if(!head){

printf("empty link\n");

return;

}

pNode p =head;

int n =getElemNum(head);

printf("this link has %d elems\n",n);

while(p){

printf("%d ",p->e);

p=p->next;

}

printf("\n");

return;

}