双向链表实现创建与修改，并文件读入读出//求修改，谢谢！
#include <iostream>#include <string>#include <cstring>#include <fstream>using namespace std;struct table{ table(){}; table(int id_t,char* name_t,int age_t,table* next_t,table* prev_t): id(id_t),name(name_t),age(age_t),next(NULL),prev(NULL){} int id; char* name; int age; table* next; table* prev;};void ofRead(char* file,table* head)//写入文件函数实现{ ofstream of(file); of.seekp(0,ios::beg); table* cur=head; do{ of<<cur->id<<' '<<cur->name<<' '<<cur->age<<' '; cur=cur->next; }while(cur==NULL); of.close();}void Create()//创建链表并写入文件{ table* head=NULL,*tail=NULL,*memory=NULL; string str("Yes"); char choice[4]=""; do{ int id,age; char* name=NULL; cout<<"input new student on the table.txt"<<endl; cout<<"input the student's id,name,and age:"<<endl; cin>>id>>age>>name; memory= new table(id,age,name); if(head==NULL&&tail==NULL) { head=memory; tail=memory; } else { tail->next=memory; memory->prev=tail; tail=memory; } printf("choose Y to go ahead,choose N to quit:"); cout.flush(); cin>>choice; }while(str==choice); ofRead("c:\\table.txt",head);}table* ifWrite(char* file)//读出文件函数实现{ static table* head=NULL,*memory=NULL;//静态存储 table* cur=NULL,*tail=NULL;//放弃尾指针 ifstream iff(file); iff.seekg(0,ios::beg); char str[8]=""; int count=0; while(iff.getline(str,sizeof(str),' '))//读出操作与存入链表中 if(++count==1) { memory = new table; if(head==NULL&&tail==NULL) { head=memory; tail=memory; memory->id=(int)str; } else { tail->next=memory; memory->prev=tail; tail=memory; memory->id=(int)str; } } else if(count==2) { memory->name=str; } else if(count==3) { memory->age=(int)str; count=0; } iff.close(); return head;}void revise(table* head,char* fname)//修改完毕并存入文件中{ cout<<"input student's id that you want to midfy"<<endl; int id_modfiy; table* cur=head; while(cur!=NULL) { if(cur->id==id_modfiy) { cout<<"1.Do you want to modify the student's id" <<"2.Do you want to modify the student's name" <<"3.Do you want to modify the student's age" <<"4.Do you want to modify the student's whole information" <<endl; int choice; cin>>choice; switch(choice) { case 1:cin>>cur->id;break; case 2:cin>>cur->name;break; case 3:cin>>cur->age;break; case 4:cin>>cur->id>>cur->name>>cur->age;break; } } cur=cur->next; } ofRead(fname,head);}int main(){ Create(); cout<<"Do you want to modify the student information?(yes or no)"<<endl; string str("yes"); char choice[4]=""; cin>>choice; if(str==choice)//选择是否文件读出与修改 { char fname[10]=""; cout<<"input student's information table file name"<<endl; cin>>fname; table* head=ifWrite(fname); revise(head,fname); } if(strcmp(choice,"no")==0) { cout<<"your operaion complete."<<endl; }}