• Ary Borenszweig (13/13) May 24 2009 When I compile this code I get "stack overflow" printed in the console.
• Moritz Warning (3/18) May 24 2009 Because you generate fact!(-1)(), fact!(-2)() and so on at compile time.
• Ary Borenszweig (3/23) May 24 2009 Thanks. Later in my head I instantiated the template and noticed the
• bearophile (5/7) May 25 2009 In time I have created similar problems in my code 2-3 times, missing a ...
• Christopher Wright (2/17) May 24 2009 Like Moritz said. You need to use "static if" there rather than "if".

Ary Borenszweig <ary esperanto.org.ar> writes:

When I compile this code I get "stack overflow" printed in the console. 
Anyone know why?

---
int fact(int X)() {
	if(X == 0) {
		return 1;
	} else {
		int temp = fact!(X - 1)();
		return X * temp;
	}
}

const someVar = fact!(0)();
---

Moritz Warning <moritzwarning web.de> writes:

On Sun, 24 May 2009 20:49:53 -0300, Ary Borenszweig wrote:

 When I compile this code I get "stack overflow" printed in the console.
 Anyone know why?
 
 ---
 int fact(int X)() {
 	if(X == 0) {
 		return 1;
 	} else {
 		int temp = fact!(X - 1)();
 		return X * temp;
 	}
 }
 
 const someVar = fact!(0)();
 ---

Because you generate fact!(-1)(), fact!(-2)() and so on at compile time.
You recursive template doesn't terminate.

Ary Borenszweig <ary esperanto.org.ar> writes:

Moritz Warning escribió:
 On Sun, 24 May 2009 20:49:53 -0300, Ary Borenszweig wrote:
 
 When I compile this code I get "stack overflow" printed in the console.
 Anyone know why?

 ---
 int fact(int X)() {
 	if(X == 0) {
 		return 1;
 	} else {
 		int temp = fact!(X - 1)();
 		return X * temp;
 	}
 }

 const someVar = fact!(0)();
 ---

 
 Because you generate fact!(-1)(), fact!(-2)() and so on at compile time.
 You recursive template doesn't terminate.

Thanks. Later in my head I instantiated the template and noticed the 
problem.

bearophile <bearophileHUGS lycos.com> writes:

Ary Borenszweig:
 Thanks. Later in my head I instantiated the template and noticed the 
 problem.

In time I have created similar problems in my code 2-3 times, missing a
"static" before some "if".
Can't the compiler help spot such bugs? If the variables a dynamic if works on
are constants (expecially if they are types) the compiler may give a warning...

Bye,
bearophile

Christopher Wright <dhasenan gmail.com> writes:

Ary Borenszweig wrote:
 When I compile this code I get "stack overflow" printed in the console. 
 Anyone know why?
 
 ---
 int fact(int X)() {
     if(X == 0) {
         return 1;
     } else {
         int temp = fact!(X - 1)();
         return X * temp;
     }
 }
 
 const someVar = fact!(0)();
 ---

Like Moritz said. You need to use "static if" there rather than "if".