so this is my multiplication function:
multiplicacion n 1 = n
multiplicacion n m = n + (multiplicacion n (m - 1))
works with integers but when attempting to multiply floats:
*Main> multiplicacion 4.1 4
16.4
that works but if the second argument is also a float, this happens:
*Main> multiplicacion 4 4.1
the function breaks.
To see what's happening, unroll the function execution - i.e. repeatedly replace function call with its body.
Let's consider the first example:
multiplication 4.1 4
= 4.1 + (multiplication 4.1 (4 - 1))
= 4.1 + (4.1 + (multiplicaiton 4.1 (3 - 1))
= 4.1 + (4.1 + (4.1 + (multiplicaiton 4.1 (2 - 1)))
= 4.1 + (4.1 + (4.1 + 4.1)
= 16.4
Now let's look at the second example:
multiplication 4 4.1
= 4 + (multiplication 4 (4.1 - 1))
= 4 + (4 + (multiplication 4 (3.1 - 1)))
= 4 + (4 + (4 + (multiplication 4 (2.1 - 1))))
= 4 + (4 + (4 + (4 + (multiplication 4 (1.1 - 1)))))
= 4 + (4 + (4 + (4 + (4 + (multiplication 4 (0.1 - 1)))))
= 4 + (4 + (4 + (4 + (4 + (4 + (multiplication 4 (-0.9 - 1))))))
= 4 + (4 + (4 + (4 + (4 + (4 + (4 + (multiplication 4 (-1.9 - 1)))))))
= 4 + (4 + (4 + (4 + (4 + (4 + (4 + (4 + (multiplication 4 (-2.9 - 1))))))))
... and so on
The second argument will never be equal to one, and therefore the first definition multiplication n 1 = n will never match, and therefore the function will forever call itself.
Your function can only multiply by positive integer numbers. Giving it a fractional number results in an infinite loop.
The problem is that you're decrementing m by 1 every call. So let's look what happens with mult 4 4.1, expanding each line:
mult 4 4.1
4 + (mult 4 3.1)
4 + (4 + (mult 4 2.1))
4 + (4 + (4 + (mult 4 1.1)))
4 + (4 + (4 + (4 + (mult 4 0.1)))))
4 + (4 + (4 + (4 + (4 + (mult 4 (-0.9)))))))
...
based on this expansion, can you see what's going wrong here? Because at no stage does m actually equal 1, you never hit the base case.
