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Full Discussion: Swap call by reference confusion
Top Forums Programming Swap call by reference confusion Post 302889406 by Corona688 on Thursday 20th of February 2014 10:46:39 AM
Old 02-20-2014
Quote:
Originally Posted by yifangt
Thanks Don!
Good I thought the same way on your swap1() function as you interpreted!
Then how is my way read?
Code:
void swap1 (int *x, int *y) 
{  
 int t;   
t = *x;   
x = y;       //Line 23
y = &t;      //Line 24
}

The reason I posted here is there was no error or warning, and it did not work the way I supposed. I must have missed important thing.
Imagine that x and y are just integers. What, exactly, will these two statements cause to happen outside the function?

Code:
x = y;
y = (anything at all);

If you said 'absolutely nothing', you are correct... The integers are passed by value, changing their value does not change anything outside the function.

Now switch them out for pointers again... What changes? Once again, absolutely nothing. You changed the values of X and Y, not their contents. Pointers are just fancy integers. Assigning something to a pointer does not magically change its contents.

Code:
// Assigning a value to a pointer
x = somethingelse;
// Assigning a value to the contents of a pointer
(*x) = somethingelse;

Last edited by Corona688; 02-20-2014 at 11:57 AM..
 

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LEARN ABOUT NETBSD

set_color

set_color(1)							       fish							      set_color(1)

NAME

       set_color - set_color - set the terminal color

set_color - set the terminal color
   Synopsis
       set_color [-v --version] [-h --help] [-b --background COLOR] [COLOR]

   Description
       Change the foreground and/or background color of the terminal. COLOR is one of black, red, green, brown, yellow, blue, magenta, purple,
       cyan, white and normal.

       o -b, --background Set the background color

       o -c, --print-colors Prints a list of all valid color names

       o -h, --help Display help message and exit

       o -o, --bold Set bold or extra bright mode

       o -u, --underline Set underlined mode

       o -v, --version Display version and exit

       Calling set_color normal will set the terminal color to whatever is the default color of the terminal.

       Some terminals use the --bold escape sequence to switch to a brighter color set. On such terminals, set_color white will result in a grey
       font color, while set_color --bold white will result in a white font color.

       Not all terminal emulators support all these features. This is not a bug in set_color but a missing feature in the terminal emulator.

       set_color uses the terminfo database to look up how to change terminal colors on whatever terminal is in use. Some systems have old and
       incomplete terminfo databases, and may lack color information for terminals that support it. Download and install the latest version of
       ncurses and recompile fish against it in order to fix this issue.

Version 1.23.1							  Sun Jan 8 2012						      set_color(1)
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