Multiply two numbers (double/float) using only + and - operators.

Question

I need to create an algorithm that could do what i wrote in the title.
Have you any ideas? I can't use any third-parts functions.

Answer 1

a * b = a + a + a + ... + a + a + a (b times)

Answer 2

Try a for loop
for ( int i = 0; i < b; i++)
{
ans += a;
}

Answer 3

Art you can just share the idea, the code is not needed.

Answer 4

Might be able to help you. Just think of how we define the multiplication of 2 numbers that have decimals. For 0.5 * 2.5 we first multiply 5 with 25 to get 125 and then we add the number of decimals that were in the first 2 numbers. The result becomes 1.25. So just use a couple of while loops, if statements and a for loop to add them.

Answer 5

Ok, but it works only if b is an integer..

Answer 6

Im going to study on it all day and going to write a code.I need to see my Idea is working or not 😁

Answer 7

Here is my solution.
https://code.sololearn.com/cIXPhFPwB0h8/#py

Answer 8

Its easy but I need better python skills 😂

Answer 9

Yes, but then you'll have to do (floor b times) +a
Then you'll have to do +a/1.(other part of b)

Answer 10

I have a few questions about your approaches. How do you know how many decimal places the numbers have? And how do you get 1.25 from 125? Is it via number<-->string conversion? But that's kind of cheating, right? Because those methods probably require multiplication and division.

Answer 11

I tried to write a code like that, but I can't calculate 0.x * 0.y

Answer 12

Art , what's the result?

Answer 13

interested as well

Answer 14

fabrizio Im very busy with my daily works going to check it on sunday

Answer 15

You are right Androidus, thats what we need

Answer 16

a*b=a+a+a(b times)

Answer 17

Kanduri Abhinay he wanted to multiply decimal numbers too.