Thread: cout question

  1. #1
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    cout question

    I have just been experimenting with the cout object and I have 2 questions.

    1. Is there any benefit of of using this
    cout << 'm' << endl; instead of this
    cout << "m" << endl; or does the compiler treat these lines
    differently at all.

    2. cout << 'A' << endl; // outputs A
    cout << 'AA' << endl; // outputs 16705
    cout << 'AB' <<endl; // outputs 16706

    can anyone explain this . I know that chars can only hold 1 byte
    but i would be interested to know how the above results are
    arrived at . Can anyone shed any light?

    Thanks.

  2. #2
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    The only time that you can use the single quote marks ( ' ) is when you are initializing a char variable. When using the iostreams (cout), you must use the double quotes ( " ) for it to display. You will get an error message otherwise.

    Although I'm not totally sure, you're probably getting a hex or oct value for the characters that you are typing in.

    Basically, there is no benefit because it is not legal. You must use double quotes to output a string in the cout stream. Hope this helps!
    Last edited by Fyodorox; 07-09-2002 at 02:50 PM.
    MS VC++ 6.0

  3. #3
    &TH of undefined behavior Fordy's Avatar
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    As I understand it....

    'm' is a char which can fit into a single byte......."m" is represented as a pointer to a NULL terminated string....they will output the same...but there is a slight difference as the "m" has a NULL after it in memory........


    'AA' is represented as 2 bytes of an int (which holds 4 on most common platforms).......so 'A' has a value of 65 on the ASCII table....which is 41 in Hexadecimal ......so 'AA' is shown in memory as 00h - 00h - 41h - 41h (00004141 Hex) and that number converted back to decimal is 16705....which is your output

  4. #4
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    Basically, use single quotes for char, which is a single character (the exception being control characters like /n, which are treated as single characters although to the human eye they're two).
    Use double quotes for anything more than one character long.
    Truth is a malleable commodity - Dick Cheney

  5. #5
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    Thanks guys ,

    that is exactly the what i wanted to know!

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