c ++ type of conversion

First, the implicit type conversion

int m = 3 + 45.6; //48.6000000000 48 truncates the fractional part truncated

Two, C-style explicit type conversion (cast)

// int k = 5% 3.2; compiler error 

int k = 5% (int) 3.2; // C language style casts, but requires the programmer to ensure that data can be transferred correctly

int k = 5% int (3.2); (one C language style cast in) // functional style cast

int k = 5% (int) "dddd"; // C language style casts, but the results are definitely wrong

// so C-style casts an unsafe type casting

Three, C ++ type conversion

// C ++ it supports C-style cast, but provided 4 C ++ casts were used for different purposes 

// purpose is to provide a wealth of meaning and function, better type checking mechanism to facilitate writing code and maintenance

1.static_cast 
2.dynamic_cast 
3.const_cast 
4.reinterpret_cast 

four casts are called "cast named"

1.static_cast: static converters (can be understood as C-style casts, but the compiler will check its legality)

// common form 

// cast name <type> (express); 1.static_cast : static converters (can be understood as mandatory C-style revolution 
  to change, but the compiler will check its legality)

  can be use on

    . a related type of transformation (such as floating point type switch integer) 
　　　　int I = static_cast <int> 100.0; 
    . B subclass conversion parent class (inheritance) 
    c.void conversion between the pointer and the other pointer * (to be cast the pointer type void *)

  Available for 
　　 a. Generally not used for conversion between different types of pointers

2.dynamic_cast: identifying a type of runtime checking mainly used. 
    It is mainly used for converting between a parent type and subtype (the pointer to the parent subtype object type)

3.const_cast: removing pointers or references attribute const (compile-time type conversion) can not be converted between different types of

4. reinterpret_cast : reinterpreting (regardless of the type of conversion process) may milling, poor security 
　　commonly used for both types of transformations as 
   a pointer to the integer conversion. 
   B the pointer type into another. type of pointer. 
   c. a pointer to an integer

IV Summary

1. The casts are not recommended, it will inhibit the compiler error

2. reinterpret_cast very dangerous, const_cast use means that a design flaw

3. If you really need to be cast, will have to use C ++ style casts

4. reinterpret_cast desirable to use as long as the rule, with the well