How to Always Return a Negative Number in Ruby?

To make sure that you always return a negative number in Ruby, you can do either of the following:

• Use Unary Minus Operator;
• Use Arithmetic Operators.

Using Unary Minus Operator

You can convert the number to its absolute form, and then negate it using the unary minus operator (-):

-n.abs

This would convert a positive number to negative and ensure that an already negative number remains unchanged. For example, you can use this in the following way:

def neg(num)
    -num.abs
end

puts neg(1234) #=> -1234
puts neg(-1234) #=> -1234

Using Arithmetic Operators

You can convert the number to its absolute form, and then negate it either by:

• Multiplying or dividing the number by -1, or;
• Subtracting the number from 0.

n.abs * -1

n.abs / -1

0 - n.abs

These would convert a positive number to negative and ensure that an already negative number remains unchanged. For example, you can use any of these in the following way:

def neg(num)
    num.abs * -1
end

puts neg(1234) #=> -1234
puts neg(-1234) #=> -1234

def neg(num)
    num.abs / -1
end

puts neg(1234) #=> -1234
puts neg(-1234) #=> -1234

def neg(num)
    0 - num.abs
end

puts neg(1234) #=> -1234
puts neg(-1234) #=> -1234