C++类型转换机制详解

C类型转换机制详解C提供了四种显式类型转换运算符和一种隐式转换机制。理解不同转换方式的用途和限制对于编写安全的代码至关重要。static_cast用于编译时已知的安全转换。#includevoid static_cast_example() {int i 10;double d static_cast(i);std::cout int to double: d \n;double pi 3.14159;int truncated static_cast(pi);std::cout double to int: truncated \n;void* ptr i;int* int_ptr static_cast(ptr);std::cout void* to int*: *int_ptr \n;}dynamic_cast用于运行时类型检查只能用于多态类型。class Base {public:virtual ~Base() default;virtual void identify() const {std::cout Base\n;}};class Derived : public Base {public:void identify() const override {std::cout Derived\n;}void derived_method() {std::cout Derived-specific method\n;}};void dynamic_cast_example() {Base* base_ptr new Derived();Derived* derived_ptr dynamic_cast(base_ptr);if (derived_ptr) {derived_ptr-derived_method();}Base* base_only new Base();Derived* failed_cast dynamic_cast(base_only);if (!failed_cast) {std::cout Cast failed as expected\n;}delete base_ptr;delete base_only;}const_cast用于添加或移除const限定符。void modify_through_const_cast(const int* ptr) {int* mutable_ptr const_cast(ptr);*mutable_ptr 100;}void const_cast_example() {int x 42;const int* const_ptr x;std::cout Before: x \n;modify_through_const_cast(const_ptr);std::cout After: x \n;}reinterpret_cast用于低级别的位模式重新解释。void reinterpret_cast_example() {int i 65;char* char_ptr reinterpret_cast(i);std::cout First byte: *char_ptr \n;long long address reinterpret_cast(i);std::cout Address as number: std::hex address \n;}隐式类型转换由编译器自动执行。class Integer {int value_;public:Integer(int v) : value_(v) {std::cout Converting v to Integer\n;}operator int() const {std::cout Converting Integer to int\n;return value_;}};void implicit_conversion() {Integer i 42;int x i;std::cout Value: x \n;}explicit关键字防止隐式转换。class ExplicitInteger {int value_;public:explicit ExplicitInteger(int v) : value_(v) {}explicit operator int() const {return value_;}int value() const { return value_; }};void explicit_conversion() {ExplicitInteger ei(42);int x static_cast(ei);std::cout Value: x \n;}类型转换是C中强大但危险的特性应该谨慎使用优先选择最安全的转换方式。