[Qxx1]

how to perform addition substraction on a 200 digit number in 'C'?????
how to read that big number??
i have to do it in float.
someone spoke of 'big float', wat is that??

[micsom_micsom]

Try using a Linked List , the Node can have the Digit, the carryover,....

Its a simple program.

[xpi0t0s]

You can't do it with the built-in types; you will have to implement your own. One way is to represent the numbers with strings, e.g.

char *pi="3.1415926535897932384626450288";

which will retain its accuracy as long as you want it to (i.e. there is no conversion to binary).

Adding/subtracting numbers will be just an implementation of how you did this back in school. Remember doing sums like this one?
12345
2008+
=====

5+8 is 13, carry 1 and write 3. 4+0+1 is 5. And so on.