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Swapping two variable value without using third variable
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*x ^= *y;
}
}
Why the test?
The test is to ensure that x and y have different memory locations (rather than different values). This is because (p xor p) = 0 and if both x and y share the same memory location, when one is set to 0, both are set to 0.
When both *x and *y are 0, all o...
Installed Java 7 on Mac OS X but Terminal is still using version 6
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Because you need to enter in Java Preferences pane and flag only the JVM 7 in this way :
To easily and quickly open the Java Preferences pane in Mac OS X you can simply call spotlight with ⌘+SPACE and type System Preferences it will show up in the last row of the window.
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Difference between malloc and calloc?
...tage of the OS's guarantee.
This means calloc memory can still be "clean" and lazily-allocated, and copy-on-write mapped to a system-wide shared physical page of zeros. (Assuming a system with virtual memory.)
Some compilers even can optimize malloc + memset(0) into calloc for you, but you should...
How do I build a graphical user interface in C++? [closed]
All of my C++ programs so far have been using the command line interface and the only other language I have experience with is PHP which doesn't support GUIs.
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How can I tell if I'm running in 64-bit JVM or 32-bit JVM (from within a program)?
... the HotSpot FAQ:
When writing Java code, how do I distinguish between 32 and 64-bit operation?
There's no public API that allows you to distinguish between 32 and 64-bit operation. Think of 64-bit as just another platform in the write once, run anywhere tradition. However, if you'd like to write c...
How do you normalize a file path in Bash?
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if you're wanting to chomp part of a filename from the path, "dirname" and "basename" are your friends, and "realpath" is handy too.
dirname /foo/bar/baz
# /foo/bar
basename /foo/bar/baz
# baz
dirname $( dirname /foo/bar/baz )
# /foo
realpath ../foo
# ../foo: No such file or directory
re...
How to join components of a path when you are constructing a URL in Python
... doing anything for me. I would like at least join("/media", "js/foo.js") and join("/media/", "js/foo.js") to work. Thanks for what appears to be the right answer: roll your own.
– amjoconn
Nov 25 '09 at 14:42
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What is the difference/usage of homebrew, macports or other package installation tools? [closed]
...install Ruby on Mac OS X you might need MacPorts, so just go with MacPorts and you'll be happy.
MacPorts is really stable, in 8 years I never had a problem with it, and my entire Unix ecosystem relay on it.
If you are a PHP developer you can install the last version of Apache (Mac OS X uses 2.2), PH...
How to install Xcode Command Line Tools
How do I get the command-line build tools installed with the current Xcode/Mac OS X v10.8 (Mountain Lion) or later?
13 Answ...
How can I get the behavior of GNU's readlink -f on a Mac?
...ption -f that follows additional links. This doesn't seem to work on Mac and possibly BSD based systems. What would the equivalent be?
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