numbers

I'm trying to compute the following number in a C program : result = (3 * pow(2,500000000) - 2 ) % 1000000000 The power of 2 is way to large to be handled properly => I'm under the impression I could split the calculation in many steps using the modulo to reduce the result size. Does someone has a strategy for doing so ? Any other idea ? Thanx in advance Manu The simplest method is exponentiation by repeated squaring reducing by the modulus in each step. unsigned long long mod_pow(unsigned long long base, unsigned long long exponent, unsigned long long modulus) { if (exponent == 0) return 1;

I don't think it is hard, just tedious to write: Some small free (as in beer) library where I can put in a String like 1,2-9,33- and it can tell me whether a given number matches that expression. Just like most programs have in their print range dialogs. Special functions for matching odd or even numbers only, or matching every number that is 2 mod 5 (or something like that) would be nice, but not needed. The only operation I have to perform on this list is whether the range contains a given (nonnegative) integer value; more operations like max/min value (if they exist) or an iterator would be

In Java - what is the faster way to find if the given integer number is starting with the digit 2 without having to convert the number into a string? String.valueOf(number).charAt(0) == '2' Jon Skeet If you wanted to avoid converting it to a string, you could just keep dividing by 10 to find the most significant digit: int getMostSignificantDigit(int x) { // Need to handle Integer.MIN_VALUE "specially" as the absolute value can't // represented. We can hard-code the fact that it starts with 2 :) x = x == Integer.MIN_VALUE ? 2 : Math.abs(x); while (x >= 10) { x = x / 10; } return x; } I don't

What are some common (or worthwhile) tests, test questions, weaknesses, or misunderstandings dealing with numeric inputs? This is a community wiki. Please add to it. For example, here are a couple sample ideas: I commonly see users enter text into number fields (eg, ">4" or "4 days", etc). Fields left blank (null) Very long numeric strings Multiple decimals and commas (eg, "4..4" and "4,,434.4.4") Boundary Value Analysis: Lower Boundary Lower Boundary - 1 (for decimal/float, use smaller amounts) Upper Boundary Upper Boundary + 1 Far below the lower boundary (eg, beyond the hardware boundary

Possible Duplicate: Is it possible to customize an input field for amounts with +- buttons? how to make + (plus) and - (minus) value buttons for <input type="number" class="numbertype" value="10"> ? I think it's possible to do with jQuery or maybe simple javascipt, but i don't know how.. I want do something like this : when you push on + button, value will be bigger for 1 (0,12,3,4,5,6.... 10000) when you push on - button, value will be smaller for 1 (10,9,8,7,6,5,4... 0) $("#minus,#plus").click(function(){ var value = parseInt($(".numbertype").val(), 10); $(".numbertype").val(value + $(this)