# Programming Challenge: Convert between units

## Hi everyone! It's been a long time since last programming challenge list, and here's a nice one I've encountered. If you search for something like 7km to AU, you'll get your answer. But how is it...

Hi everyone! It's been a long time since last programming challenge ^{list}, and here's a nice one I've encountered.

If you search for something like 7km to AU, you'll get your answer. But how is it done? I don't think they hardcoded all 23 units of distance and every conversion factor between them.

If you were programming a conversion system - how would you do it?

First of all, you have input in format that you can specify, for example something like this:

```
meter kilometer 1000
mile kilometer 1.609344
second minute 60
...
```

Then you should be able answer queries. For example `7 mile meter`

should convert 7 miles to meters, which is `11265.41`

.

Can you design an algorithm that will convert *any unit* into *any other unit*?

Edit: Some conversion rates I extracted from wikipedia:

```
ångström
0.1nm
astronomical unit
149597870700m
attometre
0.000000000000000001m
barleycorn
8.4m
bohr
0.00846
cable length (imperial)
185.3184m
cable length
185.2m
cable length (US)
219.456m
chain (Gunters)
20.11684m
cubit
0.5m
ell
1.143m
fathom
1.8288m
femtometre
0.00000000000001m
fermi
0.00000000000001m
finger
0.022225m
finger (cloth)
0.1143m
foot (Benoit)
0.304799735m
foot (Cape) (H)
0.314858m
foot (Clarke's) (H)
0.3047972654m
foot (Indian) (H)
0.304799514m
foot,metric
0.31622776602m
foot,metric (long)
0.3m
foot,metric (short)
0.30m
foot (International)
0.3048m
foot (Sear's) (H)
0.30479947m
foot (US Survey)
0.304800610
french
0.0003m
furlong
201.168m
hand
0.1016m
inch
0.0254m
league
4828m
light-day
25902068371200m
light-hour
107925284880m
light-minute
17987547480
light-second
299792458m
light-year
31557600light-second
line
0.002116m
link (Gunter's)
0.2011684m
link (Ramsden's; Engineer's)
0.3048m
metre
1m
m
1metre
km
1000m
mickey
0.000127
micrometre
0.000001
mil; thou
0.0000254
mil
10km
mile (geographical)
6082foot (International)
quarter
0.2286m
rod
5.0292m
rope
6.096m
shaku
0.303 0303m
span (H)
0.2286m
stick (H)
0.0508m
toise
1.949 0363m
twip
1.76310
yard
0.9144m
```