Here are the key differences between runtime polymorphism (dynamic polymorphism) and compile-time polymorphism (static polymorphism):

1. Resolution Time:
   - Runtime Polymorphism: The binding of the function call to the actual function implementation is resolved at runtime. The determination of which function to execute occurs during program execution.
   - Compile-time Polymorphism: The binding of the function call to the function implementation is resolved at compile-time. The determination of which function to execute occurs during the compilation phase.

2. Mechanism:
   - Runtime Polymorphism: Runtime polymorphism is achieved through inheritance and virtual functions. The base class has virtual functions that can be overridden by derived classes. The function to be executed is determined based on the actual object type at runtime.
   - Compile-time Polymorphism: Compile-time polymorphism is achieved through function overloading and operator overloading. It is resolved during compilation based on the types of arguments or operators used.

3. Execution Efficiency:
   - Runtime Polymorphism: Runtime polymorphism incurs a slight performance overhead due to the extra level of indirection involved in determining the appropriate function to call at runtime.
   - Compile-time Polymorphism: Compile-time polymorphism has no runtime overhead as the function calls are resolved at compile-time, resulting in direct function calls.

4. Flexibility:
   - Runtime Polymorphism: Runtime polymorphism allows for more flexibility as the specific function to be executed can be determined based on the actual object type, enabling dynamic behavior and late binding.
   - Compile-time Polymorphism: Compile-time polymorphism provides less flexibility as the specific function to be executed is determined based on the static type of the arguments or operators, enabling static behavior and early binding.

5. Usage:
   - Runtime Polymorphism: Runtime polymorphism is useful when you have a hierarchy of classes and want to achieve polymorphic behavior where the specific function to be executed is determined at runtime based on the object's actual type.
   - Compile-time Polymorphism: Compile-time polymorphism is useful for handling different types of arguments or operators in a uniform manner and providing different overloaded functions or operators for different combinations of types.

Both runtime polymorphism and compile-time polymorphism have their own advantages and use cases. The choice between them depends on the specific requirements and design of the program.