C ++ knowledge of discrete points

Summary

C ++ knowledge of discrete points

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• In a different source file can define (end of the current source file #define macro scope from the beginning to the) same macro
• Prevent duplicate file header contains means: to prevent the repeat of a source file that contains the same header file twice, but the same header file can be simultaneously, each containing a different source files.
• General class defined in the header file, the function defined in the default class 内联(inline), and in the class declaration, a function is not defined outside the class as a default 内联(inline).
• Variables defined in the header file is automatically added extern.
• Several methods defined functions in the header file:
  • Declaring class, define static member functions in a class, and implement functions in the header file.
  • Using a template function (which requires declarations and definitions in the header file) （没有试过）.
  • It is defined as inline functions inline.

C ++ syntax

• Negative remainder and quotient are negative. For example -123 / 10 = -12, -123 % 10 = -3.
• stringFormer type to addstd::
• Defined std::string a="123456", so a[a.length() - 1] == '6'instead '\0'.
• char a = ''We will complain because it is not initialized to empty characters. It will have to be at leastchar a = '\0'
• Note: Stack stackno reservemethod. (TODO: C ++ prime or algorithm design and analysis seems to have summed up what the structure contains reserve, look)
• Note that the vector size is unsigned. For example vector<int> aa;, when a aa.size()is 0, aa.size()-1not -1 but a maximum unsigned number.

C ++ library functions

• int isalnum ( int c ): 头文件\<ctype\>Check character is not a letter or number (alphanumeric).
• int tolower(int c);: , 头文件\<ctype\>A character will be converted to lowercase characters.

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