Thread: Help with Do While loop

take " ofstream a_file("test.txt",ios::app);" outside the loop. you only need to open a file once. Remember to close it with a_file.closed();

Code:

question[200]

you're trying to access the 201st character, not the entire character string. So , you must take out the [200] in the do-while loop.

This is not my first program. Thanks for your input.

Change your question from using a char array to std::string. Use std::getline to read string instead of std::cin.getline. No need to use std::cin.ignore when using std::getline. Files never need to be closed explicitly. They close automatically when they go out of scope, so no call to close() needed.

Perhaps the problem is that you think it doesn't run the code, but it really does.
See SourceForge.net: Pause console - cpwiki.

I actually Khabz had a good point earlier, although maybe it came across as a bit sharp! I'm new to this as well and I'm not at writing to text files yet even after hours and hours and studying loops/functions and basic stuff.

Code:

while (x!=2);

This seems unnecessary to me. As I said, I'm new to this as well, but your instructions says "Press 1 to enter another question". With this condition, I could press anything that is not a '2'. Why not:

Code:

while (x==1);

i.e. "Press 1 to enter another question"

And this bit:

Code:

std::cin.getline(question,200);

My beginners learning (thanks to Alex and his book!) tells me to use:

When you read in strings, sometimes you want to read a whole line at a time. There is a special function, getline, which can be used to read in the whole line. It will even automatically discard the newline character at the end.

To use getline, you pass in a source of input, in this case cin, the string to read into, and a character on which to terminate input. For example, the following code reads the user's first name:

getline( cin, user_first_name, '\n' );

- Alex Allain, Jumping into C++

And do you even need to put std:: in front of cin? Namespace std is being used so I'm not sure you need to. There's no std:: in front of cout in your code.

Anyway, I can't really help much further as I don't even know what [200] does! Looking at others' code certainly helps me though. I'm sure the experts here can offer much more than myself, but I'm working on that

good things there, nice one. In response to your later query - using namespaces is not always preferred, there has been quite a bit of discussion on that you can find on these pages. But declaring the namespace and then using that scope operator gives compiler warnings, i say that but i was unable to replicate one i got recently for just that reason, writing into an old file i forgot it was there... maybe thats part of the problem with them..

Hey thanks for your reply sam. I've been studying and praticing C++ for over a month now and written over 20 programs prior to this. I started off with "Hello world" just like everyone else and gradually worked my way up to this. I have used every component of this program in other simpler examples but there comes a time where you have to move up to the more difficult things. Really, considering how in-depth C++ is, this program is extremely simple and a good first project. I'm bound to run into trouble but thats part of learning. Challenging yourself and asking for help when you are stumped. Thats just some advice from one beginner to another. Learn the basics first but don't be afraid to apply what you learned to real world projects early on. It will motivate you. Oh and Writing to text files is not difficult. Its easier than loops and functions. It was actually the easiest part of this whole program.

As for your inputs? Yes I realized that std was not necessary and removed it.

The the while statement was set that way it because I want to limit the user to only two possible inputs. I'm working on code that will produce an error message if the wrong input is detected. What I wanted to to first was start simple and get the program working and then add these things later.

I tried to use getline() but i got an error message but a few people have suggested it so I will retry it. Good luck in your studies.

Originally Posted by Elysia

Perhaps the problem is that you think it doesn't run the code, but it really does.
See SourceForge.net: Pause console - cpwiki.

I don't know if that was a hint on your part but you were right. The code was running. The problem was a value was being passed to the cin.get() which caused the program to terminate. I fixed the problem by inserting a second cin.get() under the first one. That kept the program running long enough for me to see the closing message. Here is my new code:

Code:

#include <iostream>
#include <fstream>
#include <limits>
#include <string>

using namespace std;

int main ()
{
    string question;
    int x;
    
    
    ofstream a_file("test.txt",ios::app);
        do
        {
            cout<<"Enter a question:\n\n";
            getline(cin,question);
            a_file<<question<<"\n";
            cin.clear();
            cin.ignore(numeric_limits<streamsize>::max(), '\n');
            cout<<"Would you like to enter another question?\n";
            cout<<"1 for yes. 2 for no: ";
            cin>>x;
            
        }
        while (x!=2);
        
    a_file.close();
    cout<<"\nYour submition has been saved. Have a nice day!\n";
    cout<<"Press enter to close the program.";
    cin.get();
    cin.get();
    
}

Everything is solved now thanks guys for your help.