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详细说明： Why Learn C? The most popular Operating Systems right now are Microsoft Windows, Mac OS X, and /Linux. Each is written in C. Why? Because Operating Systems run directly on top of the hardware. There is no lower layer to mediate their requests. Originally, this OS software was written in the Assembly language, which results in very fast and efficient code. However, writing an OS in Assembly is a tedious process, and produces code that will only run on one CPU architecture, such as the Intel X86 or AMD64. Writing the OS in a highe r level language, such as C, lets programmers re-target the OS to other architectures without re-writing the entire code. But why 'C' and not Java or Basic or Perl? Mostly because of memory allocation. Unlike most computer languages, C allows the programmer to address memory the way he/she would using assembly language. Languages like Java and Perl shield the programmer from having to worry about memory allocation and pointers. This is usually a good thing. It's quite tedious to deal with memory allocation when building a high-level program like a quarterly income statement report. However, when dealing with low level code such as that part of the OS that moves the string of bytes that makes up that quarterly income report from the computer's memory to the network card's buffer so they can be shipped to the network printer, direct access to memory is critical -- something you just can't do with Java. C can be compiled into fast and efficient machine code. So is it any wonder that C is such a popular language? Like toppling dominoes, the next generation of programs follows the trend of its ancestors. Operating Systems designed in C always have system libraries designed in C. Those system libraries are in turn used to create higher-level libraries (like OpenGL, or GTK), and the designers of those libraries often decide to use the language the system libraries used. Application developers use the higher-level libraries to design word processors, games, media players, and the like. Many of them will choose to program in the language that higher-level library uses. And the pattern continues on and on and on... ← Why learn C? | What you need before you can learn → ...展开收缩
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