求解 这题用c语言怎么做？

struct {
char out;
char name[20];
char srccity[20];
char tarcity[20];
}Node;

//做一个链表，把游客信息存进去,out = 0；
输出始发城市阶段,遍历链表
while(pt != NULL)
{
if(pt->out != 0){pt = pt->next;continue;}

list = pt;

printf("%s :",list->srccity);
while(list != NULL)

{
if(list->out == 0 && 0 == strcmp(list->srccity,pt->srccity))

{
list->out=1;

printf(" %s",list->name);

}
list = list->next;

}
putchar('\n');

pt = pt->next;

}