variables larger than floats

So I am having trouble with numbers bigger than floats.

A few questions. Can the variable type

hold decimal places. I think it doesnt.

I am running an iterative calculation in a for loop that runs 100 times. The first few answers are small enough for a float to hold - need up to 8 decimal places. But then they become to big for floats, so I wanted to hold them all in long long type variable. But it doesnt seem to store decimals.

Please can someone tell me a veriable type, that is very large, but can also hold decimals. And what the code is when printing or scanning for one.

i.e printf("%d", int);

the %d is the "code for integers".

Thanks

Alex