●编译通过,运行出错?

#include "stdio.h"
struct block{
struct block *pre;
int addr;
int length;
int worknum;
struct block *next;};

void viewprint(struct block *head){
struct block *now=head;
int i;
printf("addr/*worknum length\n");
do{
if(now->worknum==0){
printf("%d %d",now->addr,now->length);
for(i=1;i<=now->length;i++)
printf("-");}
if(now->worknum!=0){
printf("\n *%d %d",now->worknum,now->length);
for(i=1;i<=now->length;i++)
printf("*");}
now=now->next;
}while(now!=NULL);}

void provideblock(struct block *head,int howlarge,int worknumm){
struct block *now=head;
do{
if(now->length<howlarge){
now=now->next;
continue;}
else break;}
while(now!=NULL);