A type cast is an override within an expression that causes the compiler to generate conversion code and to treat the item as if it had a different type.
int a = 13;
int b = 4;
float c;
c = a / b; /* result is 3, the integer value of 13 divided by 4 */
c = (float) a / b; /* result is 3.1, the floating value of 13 divided by 4 */
In this case, the (float) keyword was the typecast. Note also that it was not necessary to typecast b, because the compiler recognizes the mixed mode expression.
In order to implement automatic type casting you must provide conversion operator overloads in your object's class definition. Generally it is best not to provide conversion operators unless absolutely necessary; it is always better to implement conversions using explicit member methods instead. However, if you should require a conversion operator, the operator should simply invoke the method.
For instance, if your object can be converted to a std::string object, then you should provide an as_string() method that returns a std::string by value. For automatic conversion, you should provide a conversion overload that invokes the as_string() method:
class foo{
//...
public:
std::string as_string()const;
operator std::string(void)const;
};
std::string foo::as_string()const{
//...
}
foo::operator std::string()const{
return(as_string());
}
Note that conversion operators have no return type since the return type is implied by the operator name.
Automatic type casting is implicit, whereas (non-automatic) type casting is explicit.
The same as in C, struct.
char x = "C"; if(char == 'C') { } else { }
same the types used in C. that is int...char...float...
no
these are difference in between c and c++: a) C is a SPL and C++ is a OOP. b) C has not concept of object but C++ has this feature. c) C has not 'class' name data type but C++ has.
The same as in C, struct.
Use "typedef" : both in C and C++.
char x = "C"; if(char == 'C') { } else { }
int i = 42; char c = ( char ) i; // explicit cast double d = i; // implicit cast
Object-oriented programming and stricter type-safety.
type operator- ();
same the types used in C. that is int...char...float...
Yes, you can cast in C++, both statically and dynamically. Objects can also be cast provided the class designer implemented the appropriate conversion operators.
no
doesn't return the value.
these are difference in between c and c++: a) C is a SPL and C++ is a OOP. b) C has not concept of object but C++ has this feature. c) C has not 'class' name data type but C++ has.
A declaration is an incomplete type whereas a definition is a complete type.