Thread: Annoying Message Box Problem

Show some code. What message box are you using from what library? Sometimes, there will be arguments which specify if the message box pops up on top or in the back.

Another possibility, I suppose, is that your message box is popping up in front and getting pushed to the back because something else happens in the console which is then pushed up front.

Sorry, this has absolutely nothing to do with my messagebox question, but how can I convert a string to an int?

Ta

Or even better, what is a function similar to this, except it is used for ints : intname.erase(intname.size()-1);

Hi:

About your question of the console, since console apps (in Win32) are like meant to be run MS-DOS (and MS-DOS don't have Windows handles ), you might want to see some API for this.

As for string -> int see atoi

You just want to get rid of the last digit?

Code:

int x = 12345;
x /= 10;

And you should stick with one all the way: console or API. Intermixing stuff may produce undefined behaviour.

Code:

        cout<<"\n\n\n    This is the content of the file:\n\n    "<<content<<"";

Why the extra "" at the end?

Okay, I did a little experiment using the 'age program' from the tutorials, and I know realize that it does infact take off one digit only. However, something beyond my understanding has occured. Here's my code:

Code:

#include <iostream>
#include <conio.h>
#include <windows.h>

using namespace std;

void mainfunction();

void mainfunction()
{
    char age;
    int size = 0;
    int agefull;
    
    system("cls");
    
    cout<<"Please insert your age:    ";
    
    while ( age != '\n' && age != EOF && age != '\r' )
    {
        age = getch();
        
        if ( age == '\b' && size > 0 )
        {
            cout<<"\b \b";
            size--;
            agefull /= 10;
        }
        
        else
        {
            if ( isdigit(age) && size < 3 )
            {
                cout<<age;
                agefull += age;
                size++;
            }
        }
    }
    
    cout<<"\n\n\n";
    
    if ( agefull < 100 )
    {
        cout<<"You are pretty young!";
    }
    
    if ( agefull == 100 )
    {
        cout<<"You are old.";
    }
    
    if ( agefull > 100 )
    {
        cout<<"You are really old.";
    }    
}     

int main()
{
    char input;
    
    cout<<"Do you wish to run this program ?\n\nY = Yes\nN = No\n\n";
    input = getch();
    
    while (input != 'y' && input != 'Y' && input != 'n' && input != 'N')
    {
        input = '\0';
        input = getch();
    }
    
    cout<<input<<"";
    Sleep(1000);
    
    switch (input)
    {
        case 'y':
            
            mainfunction();
            
        break;
            
        case 'n':
            
            return 0;
            
        break;
        
        case 'Y':
            
            mainfunction();
            
        break;
        
        case 'N':
            
            return 0;
            
        break;
        
        default:
            
            cout<<"\n\nError. Execution Terminated.\nPress any key to exit the program.";
            input = getch();
            return 0;
            
        break;
        
    }
    
    cout<<"\n\n\nPress any key to exit the program.";
    input = getch();
}

The program kept saying you are really old, so I told it to print 'agefull' after a key was pressed or if backspace was pressed, and it came out with stupid numbers. Compile it and see for yourself. What the hell is going on ?

Please help me, this is so frustrating.

P.s. A few notes:

1. I know that on the switch statement, I don't really need default, but I put it there just as a precaution.

2. I don't really know what EOF, and \r are in the main function while loop. Would any one be so kind as to explain them to me. I found them on the FAQ about getch(), and I thought I'd better use them, because they worked fine in my other programs.

Thanks.

1. You could at least make the response case-insensitive. There are cleaner ways to do this I guess, but you could fall-through

Code:

case 'Y':
case 'y':
    mainfunction();
    break;
case 'N':
case 'n':
    cout << "Error with input. Closing...\n";
    break;

Use of default is good.
I never understood things like this though, if people want to run the program, they run it. No need to ask.

2. getch is a bit of a stretch for something like this, you could do the same thing with standard input devices.
Basically we check all those characters and EOF because we never want to get stuck in a loop.
Supposing that you're only doing this to learn how getch works, to truly understand it, you have to wrap your head around the concept of keyboard buffering (thanks quzah! It might be a bit fishy why I have to defer the real explanation to someone else. heheh... ) Enter is one of those weird functional keys, where both a carriage return \r and a newline \n appear in the console. It's important to check for both of these characters when using getch because getch only grabs the first part of the keystroke.
But that is not the only way the user can signal the end of input. If he's really clever, he could simulate EOF (end of file) and stop recording. You need to check for that also.

As a parting gift:

Code:

#include <iostream>
#include <limits>
int main( ) {
        int age;
        std::cout << "Enter your age please: ";
        while(!(std::cin >> age)) {
            std::cin.clear();
            std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
            std::cout << "Enter your age: ";
        }

        if(age < 100)
            std::cout << "You're really young.\n";
        else if(age > 100)
            std::cout << "You're ancient!\n";
        else
            std::cout << "You're old.\n";
        return 0;
}

$ ./age
Enter your age please: jfirijgkagf  
Enter your age: 21
You're really young.

Owner@PAVILION ~
$

Thanks Citizen! Oh and also thanks to quzah for your detailed explaination on keyboard buffering. I understand Getch() alot more though now.

Cheers again.
Necrofear.

EDIT: Oh, hold on. Eventhough I understand getch() (well, a little more, anyway) I would still like to know what was wrong with the code so I don't make the same mistake again. Why does them wierd numbers come up? Any ideas?

Ta

What do you mean 'No go debug' ?

Oh, and I was just testing that atoi thing you showed me, but it says invalid conversion from 'char' to 'const char*' . It doesn't matter, I was just wondering how it could be done.

EDIT: Oh right, you changed it. Cheers

How come people keep deleting messages ?

Oh, I understand now

Because you keep editting yours.