Question

I’m brand new to programming and Ruby is my first language. One exercise I’m working on is to create a multiplication table that does the following:

1x1 = 1
1x2 = 2
(etc)
2x1 = 2
2x2 = 4

I figured I’d do this by creating a nested while loop:

a = 1
b = 1

while a <= 5
    while b <= 5
        puts "#{a} * #{b} = #{a * b}"

        b += 1
    end
    a += 1  
end

When I run the script it prints the first set of times table (1×1 – 1×5) then stops. It doesn’t iterate the parent loop. What am I doing wrong?

Answer 1

You never reset your b to 1. Look at the second while loop:

while b <= 5:
    ...
    b += 1

At the end of this loop, b = 6, and the loop exits. Then a += 1 is executed, and our outer loop begins. On all the next inner loop iterations, b = 6 however, and therefore isn’t executed. Thus you need:

...
end
a += 1
b = 1