Cin.get()

This is a discussion on Cin.get() within the C++ Programming forums, part of the General Programming Boards category; I have one question using cin.get(). I have posted the code below. The problem is, when I run the program ...

  1. #1
    Microsoft. Who? MethodMan's Avatar
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    Cin.get()

    I have one question using cin.get(). I have posted the code below. The problem is, when I run the program it terminates right away, and doesnt wait for the user to input the information. Why?
    Code:
    void get_info()
    	{
    		cout << "Enter the blocker hand (L or R)";
    		cin.get(blocker_hand, HAND);	
    		cout << endl;
    		cout << "Enter the glove hand (L or R)";
    		cin.get(glove_hand, HAND);
    	}
    // declerations
    private:
    char glove_hand[HAND];
    char blocker_hand[HAND];
    and HAND is a constant of length 1.

    There is more code to the actual program, but this is the only part causing the problem.

    Thanks
    -MethodMan-

    Your Move:Life is a game, Play it; Life is a challenge, Meet it; Life is an opportunity, capture it.

    Homepage: http://www.freewebs.com/andy_moog/home.html

  2. #2
    Guest Sebastiani's Avatar
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    There are two problems. First, the minimum length for a string is 2 chars, period. That accomadates a single char and the null-terminating zero. Second, cin.get() does not flush the newline character from stdin. Try instead:

    Code:
    const int HAND = 2;
    char blocker_hand[2];
    char glove_hand[2];
    //....
            cout << "Enter the blocker hand (L or R)";
    		cin.get(blocker_hand, HAND);	
    		cout << endl;
                                    fflush(stdin);
    		cout << "Enter the glove hand (L or R)";
    		cin.get(glove_hand, HAND);
    //...
    Cheers.
    Code:
    if( numeric_limits< byte >::digits != bits_per_byte )
        error( "program requires bits_per_byte-bit bytes" );
    24bbs.cpp

  3. #3
    Microsoft. Who? MethodMan's Avatar
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    Thanks, I forgot obout the terminating character. It still, however, does not let me get the second input.
    -MethodMan-

    Your Move:Life is a game, Play it; Life is a challenge, Meet it; Life is an opportunity, capture it.

    Homepage: http://www.freewebs.com/andy_moog/home.html

  4. #4
    Guest Sebastiani's Avatar
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    Did you forget to use fflush()? It should be placed between the two inputs as my post described. If all else fails, use the time - honored fgets()!
    Code:
    if( numeric_limits< byte >::digits != bits_per_byte )
        error( "program requires bits_per_byte-bit bytes" );
    24bbs.cpp

  5. #5
    elad
    Guest
    i've read several knowledgeable sources that recommend avoiding use of C style buffer handling (fflush) and C++ style buffer handling (get()) in the same program. My advice is to use getline() in place of get(). getline() will remove the terminating char from the buffer, whereas get() and >> will not. Alternatively, use ignore() with reasonable parameters.

  6. #6
    End Of Line Hammer's Avatar
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    When all else fails, read the instructions.
    If you're posting code, use code tags: [code] /* insert code here */ [/code]

  7. #7
    Code Goddess Prelude's Avatar
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    Code:
    const int HAND = 2;
    char blocker_hand[2];
    char glove_hand[2];
    //....
        cout << "Enter the blocker hand (L or R)";
        cin.get(blocker_hand, HAND);	
        cout << endl;
        fflush(stdin);
        cout << "Enter the glove hand (L or R)";
        cin.get(glove_hand, HAND);
    //...
    You've been here long enough to know better than that Sebastiani. fflush ( stdin ) is undefined and there are better ways to do this in C++. Look into cin.ignore() for a good way to discard extraneous characters in the input stream.

    -Prelude
    My best code is written with the delete key.

  8. #8
    Guest Sebastiani's Avatar
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    Contrary to what everyone seems to say about fflush(), it works fine on my compilers, though again, I never use fflush() since I am comfortable with fgets() and hence never need it, (nor cin or scanf() for that matter). But you are right. No sense in teaching others bad habits
    Code:
    if( numeric_limits< byte >::digits != bits_per_byte )
        error( "program requires bits_per_byte-bit bytes" );
    24bbs.cpp

  9. #9
    Code Goddess Prelude's Avatar
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    >Contrary to what everyone seems to say about fflush(), it works fine on my compilers
    It works peachy on mine as well, but I'd rather put my trust in the C++ standard than in Microsoft.

    -Prelude
    My best code is written with the delete key.

  10. #10
    foniks munkee
    Guest
    The problem is that Microsoft actually have examples in the VC++ help using fflush(stdin). But then again, they also have "void main()"..

  11. #11
    Banned Troll_King's Avatar
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    Re: Cin.get()

    Originally posted by MethodMan
    I have one question using cin.get(). I have posted the code below. The problem is, when I run the program it terminates right away, and doesnt wait for the user to input the information. Why?
    Code:
    void get_info()
    	{
    		cout << "Enter the blocker hand (L or R)";
    		cin.get(blocker_hand, HAND);	
    		cout << endl;
    		cout << "Enter the glove hand (L or R)";
    		cin.get(glove_hand, HAND);
    	}
    // declerations
    private:
    char glove_hand[HAND];
    char blocker_hand[HAND];
    and HAND is a constant of length 1.

    There is more code to the actual program, but this is the only part causing the problem.

    Thanks
    Not too sure because I have not used this method, but if you just want character input than:

    char a, b;

    cin >> a;
    cin >> b;

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