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reversing string

closed account (4ET0pfjN)
Why doesn't this cause infinite loop b/c if I had an array of let's say 2 elems, and I set the wrong base case as such, wouldn't front be an index that goes past last index in array?

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void reverse(int* list, int front, int end)//main calls fcn w/ arguments: &list[0], 0, (size - 1)
{
	if ( front <= end )//Q: why doesn't this cause infinite loop?
		return;
	else
	{
		//swap current front w/ current end elem
		int tmp = list[front];
		list[front] = list[end];
		list[end] = tmp;
		
		reverse(list, front + 1, end - 1);
	}
}


the correct base case is: if ( front >= end ) but I'm curious as why it compiles and when I print the array, it still prints: 1,2, rather than be an infinite loop.

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int main()
{
 int list[] = {1,2};
 reverse(list, 0, 1);
 
 for ( int i = 0; i < 2; ++i)
   cout << list[i] << " , ";

 return 0;
}


This seems simple, but how do I get the function to output the new reversed array?
Last edited on
vkrishan (9)
why would it cause an infinite loop? the value you are calling with are 0 and (length-1) so if (front <= end) condition is always satisfied whatever be your array and reverse returns without doing anything, hence the array is printed as such even after the call.
closed account (4ET0pfjN)
I forgot that the base case is reached the first time, and array is not reversed, I wasn't thinking when I posted this, thanks.
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