converting feet to metres with decimal points

but how does that count up?
metre =feet /3.28
but..

how do i use that statement to produce results as well as convert between the two in a button press? i thought seeing as its climbing through an array of sorts, i would need seperate lcd prints and sd writes?

i currently have,
turn on,
feet or metre //buttonpress
count up and show on lcd //buttonpress
count down and show on lcd //buttonpress
press enter-save to sd and show on lcd //buttonpress

id like a variable to be able to use anywhere like

int magical = 0;
magical = count;
count = inch;
inch = 1.00;
feet = inch / 12;
metre / feet/3.28

insert magical conversion code here

count up in metres or feet

ive been on this for ages and cannot find a soluton within my knowledge and heavy googling just helped confuse me more on bits and thisnumber++thatnumber,++this number?!?!?!?

im not an ignorant person and i love a challenge but i can not figure this out!