If this sentence is true, then gamedev.net does not exist.

Considering that A is the sentence itself, and "gamedev.net does not exist" is B:

if A then B

The correct result is true or false?

Edit:

String a = "If this sentence is true, then gamedev.net does not exist.";

String gamedev;

public boolean getExisting(String s){

if (s != null){

gamedev = null;

return true;

}

else{

return false;

}

}

boolean answer = getExisting(a);

1: GameDev.Net exists. (premise)

2: A => B (premise)

3: ~A v B (definition of =>)

4: Either this sentence is false or GameDev.Net does not exist. (definitions of A, B, v)

5: Either the sentence "Either this sentence is false or GameDev.Net does not exist" is false, or GameDev.Net does not exist (definition of A, again)

6: Therefore, the sentence "Either this sentence is false or GameDev.Net does not exist." is true. (or elimination on 4)

7: Therefore, GameDev.net does not exist. (implication elimination by way of 2,6)

8: Contradiction. (by 1,7)

9: Contradiction. (by way of 2, 8; since GameDev.net DOES in fact exist, and if we assume that the relation A => B is true then we get a contradiction)

10: Therefore, ~(A => B) (by 2,9)

In other words, the sentence "If this sentence is true, then gamedev.net does not exist." is false.

if ("this sentence is true, then gamedev.net does not exist.") {
    printf("Oh teh noes!!!1");
}

In Python, any string is true by default (For just existing, I suppose). The problem is with the result, for it can't be true just because the sentence is true, but, it is the case.

if "this sentence is true":
    print "Gamedev.net does not exist."

#include <iostream>
#include <string>
#include <logic>
using namespace std;

void answer(bool yesOrNo);

int main(int argc, char const *argv[])
{
	bool isLifeGoingOn = true;
	bool isThisSentenceTrue;
	bool gamedevDotNetExists = true;
	
	initBrain();
	leaveBed();
	eatPizzaOrWhateversInTheFridgeThatsNotSpoiledAndWithinValidityAndIsMinimallyApetizing();
	drinkCoffee();

	while (isLifeGoingOn)
	{
		cout << "is this sentence true?" << endl;

		if (gamedevDotNetExists)
		{
			isThisSentenceTrue = false;
			answer(false);
		}
		else
		{
			 isThisSentenceTrue = true;
			 answer(true);
		}

		cout << "Gamedev.net exits?" << endl;

		if  (isThisSentenceTrue)
		{
			gamedevDotNetExists = false;
			answer(false);

			isLifeGoingOn = false;
		}
		else
		{
			answer(true);
		}
	}
	return 0;
}

void answer(bool yesOrNo)
{
	if (yesOrNo) cout << "Yes!" << endl << endl;
	else cout << "No..." << endl << endl;
}

+1 for the time you took to write this (in your other thread)

A version with lambda and list comprehension :).

import sys
sentence = True
answer = lambda x: [sys.stdout.write("Gamedev.net does not exist.") for x in [0] if sentence is True]
answer(sentence)

A nice online python interpreter to test it.

+1 for the time you took to write this (in your other thread)

No praise for a highly descriptive function name?

Error: incomplete type "this sentence" used before definition.