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easiet way to put digits at the left side of number

This is a discussion on easiet way to put digits at the left side of number within the C Programming forums, part of the General Programming Boards category; lets say i have a long type variable for example Code: long x =43343539839853583; im looking for the best algorithm ...

  1. #1
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    easiet way to put digits at the left side of number

    lets say i have a long type variable
    for example
    Code:
    long x =43343539839853583;
    im looking for the best algorithm to put 111 for example at the left of the number(
    Code:
    final result 11143343539839853583)
    Last edited by cable; 11-04-2011 at 03:10 PM.

  2. #2
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    So I guess we're assuming that a long is 64 bits? I would just do this: x += 11100000000000000000;
    If you understand what you're doing, you're not learning anything.

  3. #3
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    If the number of digits will vary, then you need to look into using log10 to figure out the number of digits (or a division loop), and pow to get something to multiply it by to get the right number of zeros after the 111. Then you can add.
    Salem likes this.

  4. #4
    Algorithm Dissector iMalc's Avatar
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    Quote Originally Posted by itsme86 View Post
    So I guess we're assuming that a long is 64 bits? I would just do this: x += 11100000000000000000;
    Even if we were assuming that, then the constant is still missing the L suffix and is therefore of type int. Unless the compiler he is using treats both int and long as 64 bit (which I don't believe can be the case) then the first line of code he posted is a fail.
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  5. #5
    Captain Crash brewbuck's Avatar
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    Convert to string, stick "111" at the front, convert back to long?
    Code:
    //try
    //{
    	if (a) do { f( b); } while(1);
    	else   do { f(!b); } while(1);
    //}

  6. #6
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    Like this...

    Code:
    char str[32] = "111";
    
    sprintf(&str[3],"%d",number);
    
    number = stoll(str);
    Brewbuck had the right idea...

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