Can't break out of loop that creates instances
Hey guys:
I'm having trouble breaking out of a loop that takes input from a file. I can only break it if I make a code that specifies how many inputs there are and makes it stop when it reaches the max input. I think it has to do with me using these in class default constructors, but this is how it has to be done for my assignment. This is a program that simulates a messaging system.
Basically .eof(), .fail(), none of that is working
This is my first class:
This is the class that the first class refers to, the objects here create individual objects with variables containing components of a message:
And this is the textfile that fin reads from, you don't really have to read this. First number is message number, second char is status (R for read, N for New), second line is sender, 3rd line is recipient, 4th line is subject, 5th line until "EOF" is the body of the message. Just skip to the bottom, don't bother reading:
There are 20 messages in total. When I use the cheatcode that breaks the loop after 20 iterations, the whole code works perfectly, but I can't keep the code, because I need to implement a function that can compose more messages and writes them to file.
Everything gets read in perfectly, but it doesn't know when to stop and I get an infinite loop on run where it just hangs before finishing the vector. Sorry for the long post, please help. I really can't figure this out...
I'm having trouble breaking out of a loop that takes input from a file. I can only break it if I make a code that specifies how many inputs there are and makes it stop when it reaches the max input. I think it has to do with me using these in class default constructors, but this is how it has to be done for my assignment. This is a program that simulates a messaging system.
Basically .eof(), .fail(), none of that is working
This is my first class:
MailSystem::MailSystem() // class constructor that creates a vector full of all message objects { ifstream fin; // declaring fin fin.open("mail.txt"); // this is the text file // int count = 0; // this count is used to break the loop with cheat code below while (!fin.eof()) { // if (count == 20) break; /* when this is uncommented, it works, because there are only 20 messages in the text file. */ Message createMessageInstance(fin); // creates instance and passes fin to class below systemMessages.push_back(createMessageInstance); /* this is a vector previously declared and it pushes back all the messages one by one */ // count++; // increment count to cheat and bypass } } |
This is the class that the first class refers to, the objects here create individual objects with variables containing components of a message:
Message::Message(istream& fin) // this is the class constructor that creates individual message objects through initialization { fin >> messageNum; // takes input into all of these variables getline(fin, status); getline(fin, sender); getline(fin, recipient); getline(fin, subject); while (message != "EOF") // this last code gets string for message body { messageBody.append(message); if (messageBody != "") { messageBody.append("\n"); } getline(fin, message); } |
And this is the textfile that fin reads from, you don't really have to read this. First number is message number, second char is status (R for read, N for New), second line is sender, 3rd line is recipient, 4th line is subject, 5th line until "EOF" is the body of the message. Just skip to the bottom, don't bother reading:
1 R Jemma Harry What were you thinking? Harry, You seriously need to stop claiming your paperclip orders under the heading art supplies. Jemma EOF 2 R Jemma Jason I really really want to talk to you about those expense claims! Subject says it all... Jemma EOF 3 R Jason Jemma New copies in your mailbox. EOF 4 R Bob Harry True Story Hi Harry, Dell is selling computers with key loggers. Apparently the RCMP aked them to! Bob EOF 5 R Harry Jemma Art is Art It's not like I actually use them for work though... EOF 6 R Harry Jason True Story! Dell is selling computers with key loggers. Apparently the RCMP aked them to! EOF 7 R Bob Jemma I can’t believe I ate the whole thing. Hi Jemma, Your cake was delicious. I actually ate the whole thing last night. What was your secret ingredient? You promised you’d tell me after I ate it. Bob EOF 8 R Jemma Jason Expense Report Jason, The expense report you filled out was missing a 356B attachment. I'm sure you just forgot it. Please bring it over to my office when you can. Jemma EOF 9 R Jason Harry Not True Hi Harry, According to snopes.com, that isn't true. Jason EOF 10 R Jason Jemma Expense Report, Attempt 2 Hi Jemma, Sorry about that, I thought that the 67FGH report cover included that information... The new version is in your mailbox. Jason EOF 11 R Harry Bob Not True Actually, Bob, according to Snopes that isn't true. EOF 12 R Bob Jason Dinner Thursday Hi Jason, I don’t think we can make it to dinner on Thursday‐‐‐Julia’s knees aren’t what they used to be. Maybe next week? Bob EOF 13 R Jemma Bob Secret Ingredient Bob, The secret ingredient is love... just kidding. It's really tuna! I was doubtful myself until I tried it. Jemma EOF 14 R Jason Jon Jacob Jingleheimer Schmidt Challenge! I challenge you to a duel. EOF 15 R Bob Jemma What!?! Hi Jemma, You've got to be kidding, right? Bob EOF 16 N Jemma Bob Expense Report Bob, Did you turn in your expense report? I'm not seeing it in my inbox. Jemma EOF 17 N Jon Jacob Jingleheimer Schmidt Jason Oh, Really... You're on! EOF 18 N Jemma Bob Seriously. EOF 19 N Bob Harry Snopes.com Hi Harry, Thanks for the information about snopes.com, I hadn't heard of that site before. Bob EOF 20 N Jason Bob Dinner Next Week Hi Bob, Of course I knew that about Julia, I’m sorry that I didn’t think about that ahead of time. How about next Wednesday you come over for Mexican, and we’ll skip the football? Jason EOF |
There are 20 messages in total. When I use the cheatcode that breaks the loop after 20 iterations, the whole code works perfectly, but I can't keep the code, because I need to implement a function that can compose more messages and writes them to file.
Everything gets read in perfectly, but it doesn't know when to stop and I get an infinite loop on run where it just hangs before finishing the vector. Sorry for the long post, please help. I really can't figure this out...
Last edited on
Well, you haven't posted enough code to try to execute it...
But you should be testing on istream::good() for all input.
Or, more equivalently
Good luck.
But you should be testing on istream::good() for all input.
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Or, more equivalently
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Good luck.
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