Basic program of C/C + + (I.)

2. Domain Operator: C + + supports access to global variables through domain operators, C is not supported (identify for redefinition)
4. Efficiency analysis of ++i and i++:
   • Built-in type, no difference
   • Custom data types, ++i can return references, i++ only return object values (copy cost)
6. Floating-point numbers and 0 judgments
   • if (x >=-epsinon | | x <= epsinon)
7. The
8. does not borrow the swap implementation of the intermediate variable.
   • with and
   • with XOR (same as 0, different 1)

      //  with and  void  swap (int  & A, int  &b) {a  = a + b;   b  = a- b;   A  = a- b;  //  with xor   void  swap (int  & A, int  &<   Span style= "COLOR: #000000" > b) {a  = A^B;   b  = A^B; A  = A^B;}  

      

10. C and C + + differences
    • C implements the process Control and other functions in C + +.
    • The C part of C + + introduces overloads, inline functions, and exception handling. C + + includes object-oriented design content such as classes, inheritance, encapsulation, virtual functions, templates, package container classes, and so on.
    • Note: C + + has object-oriented features, but is not really object-oriented (Java).
12. extern "C"
    • Use variables and functions declared within the C library. Only the header files are needed during the compile phase, and the matching definitions are found when linking.
    • Explains that internal variables or functions are compiled and linked according to the C standard to solve the name matching problem.

Basic program of C/C + + (I.)