C + + Note fourth--types and declarations

2. Boolean quantity
1. Eg:bool b1=a==b;//This example, = is the assignment, = = is the judgment is equal, so first judge whether equal, a if equal to the value of B,B1 is true, otherwise it is false
2. BOOL is often used as the result type of a function that checks whether certain conditions are true,
   1. Eg:bool Greater (int a,int b) {return a>b}
3. BOOL can be implicitly converted to integers (any nonzero integer is true, 0 is false)
4. 1. Eg:bool a=ture;
   2. BOOL B=true;
   3. BOOL x=a+b;//Because a+b=2 is true, so X is also Tru
   4. Bool y=a|b;//a/b=1, so y is true
4. Character type
   1. A char type contains 8-bit bits number that can hold different values in 256
6. Integer type
8. Floating point Type
10. Big
12. 1. sizeof (char) = 1
    2. sizeof (short) = 2
    3. sizeof (float) = 2
    4. sizeof (int) = 4
    5. sizeof (double) = 8
    6. sizeof (void*) = 4
    7. sizeof (LONG) = 4
    8. sizeof (Longlong) = 8
    9. sizeof (BOOL) =
    10. sizeof (wchar_t) = 2
14. Void
16. 1. Used to characterize a function void f () that does not return a merit;
    2. The underlying type used as a pointer to an object of unknown type, which allows the pointer to be cast to any type of void * PV;
    3. A special example:
    4. 1. Pointer to type char:
       1. Char c= ' V ';
       2. cout<<c<<endl;
       3. Cout<<&c<<endl;//char type of data, the output address is not used & symbol
       4. cout<< (void *) c<<endl;//can be output using the (void*) pointer, which can also be coerced into other types of pointers
       5. cout<< (double *) C<<endl
       6. return 0;
18. Enumeration
20. Statement
22. 1. In addition to functions and namespaces, other declarations should end with semicolons
    2. Name of the statement
       1. The best name to get a comparative standard, easy to read. Eg:current_token
       2. Scope of the name:
          1. It is generally starting from the place where the name declaration begins to the place where the function block ends to become the scope of the name
          1. If a global variable and a local variable are the same name, the global variable is obscured locally, and if you want to call a global variable, you can do so through the scope resolution operator:: Make the call.
    3. Initialization of the Declaration
    4. 1. If not initialized: Global, namespace, local static objects are initialized to the corresponding 0
       2. However, local objects and dynamic objects are not initialized;
       3. 1. For example:
          1. Int Main () {
          1. Int x;//Here is the dynamic variable, no initial
          2. }
24. Typedef
26. 1. You can change a name to another name: typedef unsign CHAR uchar;//unsign char with a long name into the Uchar type

C + + Note fourth--types and declarations