A good answer might be:

Run the program and see!

Static View of Recursion

Writing a recursive Java program can be viewed as translating a math-like definition into Java code. The symbols of the definition are rearranged and some extra syntax is added to create Java code.

DefinitionTranslation into Java
Triangle( 1 ) = 1
Triangle( N ) = N + Triangle( N-1 )
int Triangle( int N )
{
  if ( N == 1 )
    return 1;
  else
    return N + Triangle( N-1 );
}

In this static view, if the math-like definition is correct, and you correctly translate it into Java, then the program is correct. You don't have to think about how Java does the calculation. Just check that you have correctly translated the definition.

QUESTION 10:

Is the following a correct translation of the math-like definition?

int Triangle( int N )
{
  if ( N == 1 )
    return 1;
  else
    return N + Triangle( N );
}