C + + implements Big Data multiplication

1. Test environment vs2013 Windows 7

Use the method of multiplicative, and then the unified carry, and finally convert it to a string, output.

Program code:

#define _CRT_SECURE_NO_WARNINGS#INCLUDE&LT;IOSTREAM&GT;STRUCT Bigdatamutliplie{private:char Data_a[100];char Data_ B[100];int len_a;int len_b;bool negative;bool detect_data () {len_a = strlen (data_a); len_b = strlen (Data_b); if (len_a = = 0 | | Len_b = = 0) {return false;} for (int i = 0; i < len_a; i++) {if (!) ( Data_a[i] >= ' 0 ' &&data_a[i] <= ' 9 ')) {return false;}} for (int i = 0; i < Len_b; i++) {if (!) ( Data_b[i] >= ' 0 ' &&data_b[i] <= ' 9 ') {return false;}}} Public:bigdatamutliplie () {memset (data_a, 0, sizeof (data_a)), memset (data_b, 0, sizeof (data_b)); len_a = 0;len_b = 0;} BOOL Init_data (const char *data_a, const char *data_b) {this->negative = false;if (!data_a | |!data_b) {return false;} if (*data_a = = '-' | | *data_a = = ' + ') {strcpy (this->data_a, data_a + 1); if (*data_a = = '-') {negative =!negative;}} else{strcpy (This->data_a, data_a);} if (*data_b = = '-' | | *data_b = = ' + ') {strcpy (this->data_b, Data_b + 1); if (*data_b = = '-') {negative =!negative;}} else{strcpy (ThiS->data_b, Data_b);}} char * MULTIPLIE_AB () {if (!detect_data ()) {return NULL;} int * Int_res = new int[(len_a + len_b) *sizeof (int)];//two numbers multiplied by maximum no more than two number of numbers added 99*99char * str_res = new char[(len_a + len_b + 2) *sizeof (char)]; Multiple applications two characters of space a stored symbol, a save ' memset ' (str_res, 0, (len_a + Len_b + 2) *sizeof (char)), memset (int_res, 0, (len_a + len_b) *sizeof ( int));//Take a multiplicative way and then unify the carry for (int i = 0; i < len_a; i++) for (int j = 0; J < Len_b; J + +) {int_res[i + j + 1] + = (data_a[i ]-' 0 ') * (Data_b[j]-' 0 '); The first bit is reserved for the save character carry}//processing carry for (int index = len_a + Len_b + 2-1; index >= 0; index--) {if (Int_res[index] >=) {int_re S[index-1] + = Int_res[index]/10;int_res[index] = Int_res[index]% 10;}} Int j = 0, I = 0;while (int_res[j] = = 0)//Find position not starting at 0 {j + +;} if (negative) {str_res[i++] = '-';} The int_res array is from 0-len_a + Len_b//str_res is removed from the symbol bit start to Len_a + Len_b + 1for (; i < (len_a + Len_b + 1) && J < (le N_a + Len_b); i++, J + +) {Str_res[i] = int_res[j] + ' 0 ';} Str_res[len_a + Len_b + 1] = ';d elete[] Int_res;return str_res;}; void Main () {Bigdatamutliplie Data;char *data_a = " -9999999999999"; char *data_b = "999"; Char *str_res;data.init_data ( Data_a, data_b); str_res = Data.multiplie_ab (); if (str_res) {std::cout << data_a << "*" << data_b &LT;&L T "=" << str_res << std::endl;delete[] str_res;} data_a = " -87654321";d ata_b = "+12345678";d ata.init_data (Data_a, data_b); str_res = Data.multiplie_ab (); if (str_res) { Std::cout << data_a << "*" << data_b << "=" << Data.multiplie_ab () << Std::endl;de Lete[] str_res;} data_a = " -314123123123123";d ata_b = " -64356343653564";d ata.init_data (Data_a, data_b); str_res = Data.multiplie_ab ();  if (str_res) {std::cout << data_a << "*" << data_b << "=" << Data.multiplie_ab () << Std::endl;delete[] str_res;} System ("Pause");}

C + + implements Big Data multiplication