Basic use of C + +

1 enumeration

1 enumShapeType2 {3 Circle,4 Square,5 Rectangle6 };7 8 intMain () {9 TenShapeType shape =Circle; One  A     Switch(Shape) -     { -      CaseCircle: thecout<<"shapetype.circle"<<Endl; -          Break; -      CaseSquare: -cout<<"Shapetype.square"<<Endl; +          Break; -      CaseRectangle: +cout<<"Shapetype.rectangle"<<Endl; A          Break; at     default: -cout<<"unknown!"<<Endl; -     } -  -  -  in     return 0; -};

2. const_cast

    Const inti =0; /*error C2440: ' const_cast ': cannot convert from ' const int ' to ' int ' Conversion are a valid standard Conversion, which can performed implicitly or by use of static_cast, C-style cast or Function-style cast is a valid standard conversion that can be performed implicitly, or using static_cast, C-style conversions, functional conversions*/    //Int J = const_cast<int> (i);    /*from the const INT--and int, the following 4 can be, except that the Const_cast constant conversion method is not possible, just because it is a legitimate standard conversion, in a simple way can be processed also use less advanced const_cast constant conversion*/        intj = i;//Implicit conversions    intH = static_cast<int> (i);//static_cast Static Conversion    intK = (intI//C-style conversion    intt =int(i);//function-Type conversions    /*Const INT *--and int * Using CONST_CAST constant conversion*/    int* s = const_cast<int*> (&i); /*error C2440: ' static_cast ': cannot convert from ' const int * ' to ' int * ' Conversion loses qualifiers*/    int* W = static_cast<int*> (&i); //long* L = Const_cast<long *> (&i); //error C2440: ' const_cast ': cannot convert from ' const int * ' to ' long * '

Usage of const_cast:

Returns the variable that corresponds to the constant = const_cast< the type > (constant) to which the constant belongs

The principles of conversion are:

const INT *--and int *

Basic use of C + +