Java big data class

Import Java. math. bigdecimal; import Java. math. biginteger; public class biginter {// default division operation precision, that is, the number of decimal places to be retained Private Static final int default_div_scale = 10; // This class cannot be instantiated private biginter () {}/*** provides precise addition operations. * @ Param V1 add count * @ Param V2 add count * @ return and */public static double add (double V1, double V2) {bigdecimal b1 = new bigdecimal (double. tostring (V1); bigdecimal b2 = new bigdecimal (double. tostring (V2); Return (b1.add (B2 )). doublevalue ();}/*** provides precise subtraction. * @ Param V1 subtrahend * @ Param V2 subtrahend * @ Return Difference Between Two Parameters */public static double sub (double V1, double V2) {bigdecimal b1 = new bigdecimal (double. tostring (V1); bigdecimal b2 = new bigdecimal (double. tostring (V2); Return (b1.subtract (B2 )). doublevalue ();}/*** provides exact multiplication. * @ Param V1 multiplier * @ Param V2 multiplier * @ return product of two parameters */public static double MUL (double V1, double V2) {bigdecimal b1 = new bigdecimal (double. tostring (V1); bigdecimal b2 = new bigdecimal (double. tostring (V2); Return (b1.multiply (B2 )). doublevalue ();}/*** provides (relatively) Precise Division operations. In case of division, the number of digits after the decimal point is accurate to *, and the number after the decimal point is rounded down. * @ Param V1 divisor * @ Param V2 divisor * @ return two parameter vendors */public static double Div (double V1, double V2) {return Div (V1, V2, default_div_scale);}/*** provides (relatively) accurate Division operations. In case of division, the scale parameter determines * the precision, and the number is rounded down. * @ Param V1 divisor * @ Param V2 divisor * @ Param scale indicates the number of digits after the decimal point. * @ Return operator of two parameters */public static double Div (double V1, double V2, int scale) {If (scale <0) {system. err. println ("division accuracy must be greater than 0! "); Return 0;} bigdecimal b1 = new bigdecimal (double. tostring (V1); bigdecimal b2 = new bigdecimal (double. tostring (V2); Return (b1.divide (B2, scale, bigdecimal. round_half_up )). doublevalue ();}/*** calculate the factorial! * @ Param n any int greater than or equal to 0 * @ return n! Value */public static biginteger getfactorial (int n) {If (n <0) {system. Err. println ("n must be greater than or equal to 0! "); Return New biginteger ("-1 ");} else if (n = 0) {return New biginteger (" 0 ");} // Replace the array with a string and construct biginteger result = new biginteger ("1"); For (; n> 0; n --) {// convert the number N into a string, and then construct a biginteger object to multiply result = result with the existing result. multiply (New biginteger (New INTEGER (n ). tostring ();} return result;} public static void main (string [] ARGs) {// What will be seen if we compile and run the following program? System. out. println (0.05 + 0.01); system. out. println (1.0-0.42); system. out. println (4.015*100); system. out. println (123.3/100); // 0.060000000000000005 // 0.5800000000000001 // 401.49999999999994 // 1.2329999999999999 // calculate the factorial. You can set N to a greater int n = 30; system. out. println ("Calculate the factorial of N" + N + "! = "+ Biginter. getfactorial (n); // use double to construct bigdecimal bd1 = new bigdecimal (0.1); system. out. println ("(bd1 = new bigdecimal (0.1) =" + bd1.tostring (); // use string to construct bigdecimal bd2 = new bigdecimal ("0.1"); system. out. println ("(bd2 = new bigdecimal (\" 0.1 \ ") =" + bd2.tostring (); bigdecimal bd3 = new bigdecimal ("0.10 "); // The equals method compares whether two bigdecimal objects are equal, returns true if they are equal, and returns false system if not. O Ut. println ("bd2.equals (bd3) =" + bd2.equals (bd3); // false // The compareto method compares the sizes of two bigdecimal objects. Equal returns 0, less than-1, if the value is greater than 1. System. out. println ("bd2.compareto (bd3) =" + bd2.compareto (bd3); // 0 // accurately calculates the system. out. println ("0.05 + 0.01 =" + biginter. add (0.05, 0.01); system. out. println ("1.0-0.42 =" + biginter. add (1.0, 0.42); system. out. println ("4.015*100 =" + biginter. add (4.015, 100); system. out. println ("123.3/100 =" + biginter. add (123.3, 100 ));}}

It is much easier to write than C ++...

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