Calculator application

I need a calculator that can handle calculations of any length. It should only be limited to the computer that it is on. The features that I need on it are as follows function example Addition (x+y) subtraction (x-y) multiplication (x*y) division (x/y) factorization (x=2*2*2*3) exponents (x^y) Factorials (x!) Permutations and combinations (ab,ba) I will want to come out with a version 2.0 that will have more features then that but this will do for now. I want to have a progress bar for the exponents and factorials and an estimated time til completion. For instance say I wanted to know what 100000000! was. This is a really large number and has 100000000 calculations. I want the program to estimate how long it will take to calculate that given the current amount of processing power it has at that time. Now I know that for some equations that would be infinte such as if I wanted to try to find pi it would be impossible to estimate anything other then forever. ## Deliverables I want a progress bar with a percentage inside. It doesn't have too be too complex just 0-100% all whole numbers is necessary. I would like to have an estimated time til the next percentage. For instance if I am at 1% it will tell me how much time it will take for 2%. This is mostly so I know that it is working and the computer hasn't froze but also so that I can have a general estimate on the time factor. I want there to be a mode where the program will take all available processing power and use it towards finding its solution. The only way to get out of the mode would be to press a combination of keys on the keyboard that would be displayed on the screen so that no one forgets. While in this mode it will still display the estimated times til completion. This is for if I have a large calculation and will be away from the computer. This will help with speed. When the keys are pressed to get out of this mode all extra processing power should be freed up and only the basic processing power that the program would normally have would stay on. Also if the program got done with whatever it was doing this would also free up the processing power. I will be dealing with large numbers far bigger then a googleplex and want an option to have numbers stored in text documents. 00 The last of these special features is a little complicated and has to do with combination and permutations. I want the program to be able to read a text document and come up with whats the permutation number of all characters:: including space and linebreak:: and what value should be given for the smallest permutation number for instance say we have a file with "aasdeawqr" if each of those letters had a number we would want "a" to be equal to 1 since it appears first "s" equal to 2 since its the second different symbol. if "a" had a value of 7 it would be a larger permutation number. The program should list all the digits in the file with the value it has assigned it. the permutation number must be based on what is in the file and nothing else. so if in the file there is 3145 the permutations would not include what would happen if a 2 was involved it just finds the permutation for whats there nothing more or less then that. If there are 20 "a" and 23 "b" it would only count out what the permutation number would be for 20 "a" and 23 "b"