Moving data

This is a discussion on Moving data within the C++ Programming forums, part of the General Programming Boards category; Hey is there fast way to move data between different types? I had in delphi function called move so i ...

  1. #1
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    Moving data

    Hey is there fast way to move data between different types?

    I had in delphi function called move so i could do like this :

    Code:
    a,b : Integer;
    buff : array[0..3] of byte
    ....
    move(a, buff[0], 4);
    move(buff[0], b, 4);
    Is something like that in C++? I need to store integers and long ints into buffer which i need to send via TCP.

  2. #2
    Programming King Mr.777's Avatar
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    In C++, you just swap variable values.... Do you know the concept of swapping?

  3. #3
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    Hm, not really

    Do you mean something like (type *) (void) (int) ?

  4. #4
    Programming King Mr.777's Avatar
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    No , like,
    Code:
    int x=1;
    int y=2;
    int z=x;
    x=y;
    y=z;
    This is called swapping...

  5. #5
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    Quote Originally Posted by Mr.777 View Post
    No , like,
    Code:
    int x=1;
    int y=2;
    int z=x;
    x=y;
    y=z;
    This is called swapping...
    Ohh i know what you are talking about but, what swapping have to do with this

    Code:
    unsigned long a;
    BYTE myBuff[0xFFFF];
    ..
    //How to place (a) into buffer starting from 20th pos, myBuff[20]
    //So my number will be as hex in myBuff pos 20 to 24.

  6. #6
    Programming King Mr.777's Avatar
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    I think, pointers can help you......
    As pointers directly refers to the memory addresses.
    May be something like this....
    Code:
    BYTE * ptr=myBuff[0];
    ptr+=20;
    *ptr=a;

  7. #7
    Registered User whiteflags's Avatar
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    You could learn about bit manipulation and make an attempt that way. In particular shifting and AND are going to be useful. OTOH, memcpy will probably work too.

  8. #8
    Programming King Mr.777's Avatar
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    Instead of using memcpy, i'll recommend memmove........

  9. #9
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    Which one is correct? That later i everybody can read from buffer corectly not from behind?

    Code:
    buff[3] = a;
    buff[2] = a >> 8;
    buff[1] = a >> 16;
    buff[0] = a >> 24;
    Code:
    buff[3] = a >> 24;
    buff[2] = a >> 16;
    buff[1] = a >> 8;
    buff[0] = a;

  10. #10
    Programming King Mr.777's Avatar
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    I belive first one as you will shift to the number of bits after you get the value...
    And the second one will shift you more far......
    What do you say?

  11. #11
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    So i can shift like that whole string to buff increasing number of bits by 8 every time?

  12. #12
    Programming King Mr.777's Avatar
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    Yes, you can.....

  13. #13
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    What's wrong with this def?

    Code:
    typedef BYTE[4] BLOCK;

  14. #14
    The larch
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    A typedef looks exactly the same as a variable declaration, except for the typedef keyword.

    Code:
    BYTE block[4]; //block is an array
    
    typedef BYTE block[4]; //block is another name for BYTE[4]
    I might be wrong.

    Thank you, anon. You sure know how to recognize different types of trees from quite a long way away.
    Quoted more than 1000 times (I hope).

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