how many times will a function print to the console? [closed]

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This question does not appear to be about programming within the scope defined in the help center.

Closed 9 years ago.

开发者_如何学Python Improve this question

I have the following snipet :

public class A

public A(int n)
{
    for (int i=0; i<n; i++)
    {
        new A(i)
    }
    console.writeln("?")
}

for a given n - how many "?" will be printed ?

• some testing shows the answer is 2^n. What is the way to reach the formula?
• I got to the formula F(n) = 1 + F(n-1) +... +F(1) + 1

how do I simplify it to 2^n ?

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If you cannot simplify it, perhaps you can prove it by induction.

http://en.wikipedia.org/wiki/Mathematical_induction

I don't know if this question is pertinent here... it has more to do with maths than with programming.