int main()
{
// not very related, but it's good to know other compile-time programming techniques
// preprocessor macros have limited use, but they're still valid for a
// number of programming patterns.
//
// when running the compiler, preprocessor variables can be defined. there
// variables can help to choose which code to compile. Useful for
// multi-platform code, features that the user wants in the code...
#define ALTERNATIVE 5
#ifdef ALTERNATIVE
std::cout << "yeah, compile-time programming existed before C++" << std::endl;
#else
std::cout << "but not everything will be COMPILED" << std::endl;
#endif
#ifndef SOME_UNDEFINED_PREPROCESSOR_SYMBOL
std::cout << "prints!" << std::endl;
#endif
#if ALTERNATIVE > 5
std::cout << "comparisons are valid" << std::endl;
#endif
// just to make it explicit...
std::cout << "template adding with float: " << add((int)3, (int)5) << std::endl;
// the function with templates accepts different types
std::cout << "template adding with int: " << add((float)3.7, (float)15.0) << std::endl;
int a = Const<9>::value;
std::cout << "const: " << a << std::endl;
int b = factorial<5>::value;
std::cout << "factorial: " << b << std::endl;
// traits
int j = 9;
//std::cout << "incremented: " << increment_type<decltype(j)>::increment_number(j) << std::endl;
std::cout << "incremented: " << increment_number(j) << std::endl;
// non-compiling template
std::cout << increment_number('a') << std::endl;
return 0;
}
/* change_task: modifies the integer number, and notes if the modified number
is odd or even by setting the value of the common variable Even_Number */
void change_task(void)
{
/* increment value */
const int inc_value = 1;
int i;
while(1)
{
/* change the number */
for (i = 0; i < 1000; i++)
{
increment_number(inc_value);
}
for (i = 0; i < 1000; i++)
{
decrement_number(inc_value);
}
}
}
