Large Numbers?

Questions
21

@Valgo Do you mean you want to use tables as numbers (for example 405 is {4,0,5}) and you want to be able to add two of these tables together like {3,0,8} + {4,0,5} == {7,1,3}? If so you can add tables together with metatables so this is possible to make.
Edit: I mean that tables can be added, multiplied, compared, divided, subtracted, ect. with metatables, not just added.

22

@Valgo Here’s a routine to multiple 2 strings of numbers. The strings are converted to tables and then multiplied together. I tried it with 2 strings of 2600 digits each. I’m not sure if there’s a limit other than time.

function setup()
    a="2112357909875357864211356809766864234689976"
    b="4664458987522345790875422312234680097656777"
    str=mult(a,b)
    print(str)
end   
    
function mult(str1,str2)
    local r,n1,n2={},{},{} 
    for z=1,string.len(str1) do
        table.insert(n1,tonumber(string.sub(str1,z,z)))
        table.insert(r,0)
    end    
    for z=1,string.len(str2) do
        table.insert(n2,tonumber(string.sub(str2,z,z)))
        table.insert(r,0)
    end
    for x=#n2,1,-1 do
        local carry=0
        for y=#n1,1,-1 do
            local v=r[x+y]+n2[x]*n1[y]+carry
            r[x+y]=v%10
            carry=math.floor(v/10)
        end
        r[x]=carry
    end
    if r[1]==0 then
        table.remove(r,1)
    end
    return(table.concat(r))
end