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// tracing out large numbers will go into exponent notation
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trace(1000000000000000000000000);
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// outputs: 1e+24
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var a:String = "1000000000000000000000009";
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var b:String = "12000000000000000000000001";
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// bigAdd function adds two large numbers
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trace(bigAdd(a, b));
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// outputs: 13000000000000000000000010
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-
// unclear what regular addition is doing here:
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trace(int(a) + int(b));
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// outputs: -3758096384
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function bigAdd(a:String, b:String):String{
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var answer:String="";
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var carry:int = 0;
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var zeros:int = 0;
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var i:int = 0;
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var max:int = 0;
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// obtain max variable and prepend zeros to the shortest string
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if (a.length> b.length){
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max = a.length;
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zeros = max - b.length;
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for (i= 0; i<zeros; i++) {
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b = "0" + b;
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}
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}else if (b.length> a.length){
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max = b.length;
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zeros = max - a.length;
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for (i= 0; i<zeros; i++) {
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a = "0" + a ;
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}
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}else{
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// a and b have same number of digets
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max = a.length;
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}
-
-
// add each character starting with the last (max - 1),
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// carry the 1 if the sum has a length of 2
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for (i = max - 1; i> -1; i--){
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var sum:String = String(int(a.charAt(i)) + int(b.charAt(i)) + carry);
-
-
if (sum.length == 2){
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answer = sum.charAt(1) + answer;
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carry = 1;
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}else{
-
carry = 0;
-
answer = sum + answer;
-
}
-
}
-
if (carry == 1){
-
answer = 1 + answer;
-
}
-
return answer;
-
}
This snippet demos a function called bigAdd(), which can be used to add very large numbers that the standard numerical datatypes (int, Number, etc) won't really work with. It uses a string based addition algorithm.
When I decided to write this snippet I dug around for awhile trying to find a nice elegant algorithm to port, something done without prepending zeros etc.... but I couldn't find one that suited my needs... so I just created this one from scratch. There's room for optimization and improvement but it works well enough for just playing around.
BigDecimal & BigInteger
A few months back I needed to do some programming with very large numbers. I dug around for awhile and eventually found out that java has a built in BigInteger andBigDecimal class.... I used java to write the program I had in mind, but thought it would be fun to eventually create something similar for ActionScript....
