• Roel Mathys (55/55) Jan 17 2004 I tried to calculate the factorial of an integer with templates,

Roel Mathys <roel.mathys yucom.be> writes:

I tried to calculate the factorial of an integer with templates,
the D compiler did not like it.

Is recursion not allowed in D templates?

bye,
roel

// -------------------------------------------------------
// first attempt: with specialisation it would not compile
template factor(int n)
{	
	int value()
	{
		if (n==0 || n==1) return 1;
		return n * factor!(n-1).value();
	}
}

template factor(int n : 0)
{
	int value()
	{
		return 1;
	}
}
template factor(int n : 1)
{
	int value()
	{
		return 1;
	}
}

int main()
{
	printf( "%d\n"
		  , factor!(4).value()
		  );

	return 0;
}

// -------------------------------------------------------
// second attempt: testing for end condition
// 	=> going ballistic
//	=> bug in compiler
template factor(int n)
{	
	int value()
	{
		if (n==0 || n==1) return 1;
		return n * factor!(n-1).value();
	}
}

int main()
{
	printf( "%d\n"
		  , factor!(4).value()
		  );

	return 0;
}