-7
class mail
{
void reg();
.
.
};
void mail::reg()
{
filout.write((char *)&obj,sizeof(obj)); // error occurring on compilation. undefined sysmbol obj
}
int main()
{
{ //local block
mail obj;
.
.
obj.reg();
} //end of local block
}// end of main
我該如何糾正這個錯誤。當我調用memeber函數時，對象是否被銷燬？ 我的理解是obj是當它被定義塊結束爲什麼我不能在一個方法中通過名稱引用一個類的實例？
我怎麼能寫OBJ到文件中的REG（）
感謝
破壞的完整代碼按要求：
#include<fstream.h>
#include<conio.h>
#include<string.h>
#include<process.h>
#include<stdio.h>
int user; // to keep a track of no. of users
class mail
{
public:
char un[25]; // user name
char pd[25]; // passsword
// no. of inbox messages
int ino; // no. of sent messages
int sno;
char isbj[25][25];
char ssbj[25][25];
char imsg[25][50];
char smsg[25][50]; // character array to store inbox and sent messages
void reg(); // func to sign up
void signin();
mail()
{}
~mail()
{
cout<<"DESTRUCTER AT WORK\N";
getch();
} // menu available after sign in
}; // object for 10 users
void mail::reg()
{
clrscr();
cout<<"Enter user name (enter unique name)\n";
gets(un);
cout<<"Enter password\n";
gets(pd);
ofstream filout;
filout.open("email",ios::app||ios::binary);
if(!filout)
{
cout<<"cannot open file\n";
}
else
{
ino=-1;
sno=-1;
filout.write((char *)&obj,sizeof(obj));
filout.close();
}
cout<<"You are now registered. Plz login\n";
getch();
} // end of sign up or register func
void mail::signin()
{
int f,i;
char subj[25],message[50],usrnm[25]; // temporary varibles to store
start:
clrscr();
cout<<"1.compose \n2.inbox \n3.Sent\n4.logout";
cout<<"\nEnter ur choice\n";
int ch;
cin>>ch;
switch(ch)
{
case 1:
cout<<"enter username\n";
gets(usrnm);
{ // beginning of local loop
mail temp;
ifstream filein;
filein.open("email",ios::in|ios::binary);
if(!filein)
{
cout<<"Unable to open file to read\n";
}
else
{
filein.read((char *)&temp,sizeof(temp));
while(filein)
{
if(strcmp(usrnm,temp.un)==0)
{
cout<<" User name valid\n";
f=1;
cout<<"Enter subject\n";
gets(subj);
cout<<"Enter message\n";
gets(message);
temp.ino++;
strcpy(temp.isbj[temp.ino],subj);
strcpy(temp.imsg[temp.ino],message); // copying message to recepient inbox
sno++;
strcpy(ssbj[sno],subj);
strcpy(smsg[sno],message); // copying messages to sender sent folder
cout<<"Your message has been sent successfully\n";
break;
}
else
{
}
filein.read((char *)&temp,sizeof(temp));
} // end of while
}
filein.close();
mail temp1;
long pos;
fstream fio("email",ios::in|ios::out|ios::binary);
pos=fio.tellg();
fio.read((char*)&temp1,sizeof(temp1));
while(fio)
{
if(strcmp(un,temp1.un)==0)
{
fio.seekg(pos);
fio.write((char*)&obj,sizeof(obj));
break;
}
pos=fio.tellg();
fio.read((char*)&temp1,sizeof(temp1));
}
fio.close();
mail temp2;
fio.open("email",ios::in|ios::out|ios::binary);
pos=fio.tellg();
fio.read((char*)&temp2,sizeof(temp2));
while(fio)
{
if(strcmp(temp.un,temp2.un)==0)
{
fio.seekg(pos);
fio.write((char*)&temp,sizeof(temp));
break;
}
pos=fio.tellg();
fio.read((char*)&temp2,sizeof(temp2));
}
fio.close();
} // end of block
if(f==0)
cout<<"invalid user. Please enter a valid user name\n";
getch();
break;
case 2:
if(ino<0)
cout<<"There are no messages in your inbox\n";
else
{
for(i=0;i<=ino;i++)
{
cout<<"\nMessage "<<i+1<<"\n"; // printing inbox messages
puts(isbj[i]);
puts(imsg[i]);
}
}
getch();
break;
case 3:
if(sno<0)
cout<<"There are no sent messages\n";
else
{
for(i=0;i<=sno;i++)
{
cout<<"\nMessage "<<i+1<<"\n";
puts(ssbj[i]);
puts(smsg[i]);
}
}
getch();
break;
case 4:
cout<<"Logout sucess\n";
return;
default : cout<<"wrong choice\n";
} // end of switch
goto start;
} // end of signin
void screen(void);
void signup(void);
void main()
{
clrscr();
char usrnm[25],pwd[25],s[25],c;
int i;
m:
clrscr();
screen();
gotoxy(30,4);
c=getch();
if(c=='i'||c=='I') //if user opts to sign in
{
gotoxy(62,11);
gets(usrnm);
gotoxy(62,13);
for(i=0;i< 25;i++) // getting password
{
if(i < 0)
i=0;
pwd[i]=getch();
if(pwd[i]=='\b')
{ i-=2;
cout<<"\b \b";
continue;
}
if(pwd[i]=='\r')
break;
cout<<"*";
}
pwd[i]='\0';
clrscr();
int f;
{ // local block
mail obj;
ifstream filein;
filein.open("email",ios::in|ios::binary);
if(!filein)
{
cout<<"Unable to open file to read\n";
}
else
{
filein.seekg(0);
filein.read((char *)&obj,sizeof(obj));
while(filein)
{
if(strcmp(usrnm,obj.un)==0)
{
f=1;
if(strcmp(pwd,obj.pd)==0)
{
obj.signin();
break;
}
else
{
cout<<"wrong password\n";
getch();
break;
}
} // end of if
else
{
}
filein.read((char *)&obj,sizeof(obj));
} // end of while
filein.close();
} // end of else
}
if(f==0)
cout<<"Wrong username or password\n";
getch();
goto m;
}
else if(c=='s'||c=='S') // user opts to sign up
{
signup();
getch();
goto m;
}
else if(c=='e'||c=='E') // user choose to exit
exit(0);
else
{
clrscr();
cout<<"you have entered a wrong key. please check and try again\n";
getch();
goto m;
}
} //end of main
void signup() // sign up function
{
int t;
clrscr();
{
mail obj;
ifstream filin;
filin.open("user.txt",ios::ate);
if(!filin)
{
cout<<"cannot open file\n";
}
else
{
filin.seekg(0);
filin>>t;
}
filin.close();
user=t;
++user; // incrementing no. users
ofstream filout;
filout.open("user.txt",ios::out);
if(!filout)
{
cout<<"cannot open file\n";
}
else
{
filout.seekp(0);
filout<<user;
}
filin.close();
obj.reg();
} // end of block
return;
} // end of sign up
void screen() // function for login screen
{
int i;
for(i=0;i<80;i++)
cout<<"*";
cout<<" SuperMail New to SuperMial ? Create an Account ";
for(i=0;i<80;i++)
cout<<"*";
cout<<" Press S To Sign up Already have a account Press I to sign in";
for(i=0;i<80;i++)
cout<<"-";
gotoxy(1,6);
cout<<"\n\n\n\n Super mail is built on the idea that \n it can be more intuitive,efficient and \n useful and may be even fun:\n\n Lots of space\n\n Less spam";
gotoxy(1,22);
for(i=0;i<80;i++)
cout<<"-";
gotoxy(32,23);
cout<<"PRESS E TO EXIT";
gotoxy(1,24);
for(i=0;i<80;i++)
cout<<"-";
gotoxy(50,10);
cout<<"-------------------------------";
gotoxy(50,11);
cout<<"| USERNAME : |";
gotoxy(50,12);
cout<<"-------------------------------";
gotoxy(50,13);
cout<<"| PASSWORD : |";
gotoxy(50,14);
cout<<"-------------------------------";
}
還有其他的錯誤也 感謝
真實的代碼和真正的錯誤信息呢？ – PlasmaHH
它真的很長。你不會去讀它。所以我縮短了它 –
讓我們決定是否要閱讀它。總是發佈完整的錯誤消息！ – Pubby