#include
     
      #include
      
       using namespace std;class BigNumberMutiplication{private:    char *num1;    char *num2;    char *result;    int lenNum1;    int lenNum2;    void reverseNumerbs();    void reverseNumber(char *s);public:    BigNumberMutiplication(char *num1,char *num2);    char *Mutiplicate();    void Test();};BigNumberMutiplication::BigNumberMutiplication(char *num1,char *num2){    this->num1=num1;    this->num2=num2;    this->lenNum1=strlen(num1);    this->lenNum2=strlen(num2);    int len=this->lenNum1+this->lenNum2+1;    result=new char[len];    memset(result,'0',len*sizeof(char));    result[len-1]='\0';}void BigNumberMutiplication::reverseNumber(char *s){    int len=strlen(s);    int i=0;    while(i
       
        num1);    reverseNumber(this->num2);}void BigNumberMutiplication::Test(){    cout<
        
         num1<
         
          <
          
           num2<
           
            reverseNumerbs(); cout<
            
             num1<
             
              <
              
               num2<
               
                reverseNumerbs(); int i=0; int j=0; for(i=0;i
                
                 lenNum1;i++) { int incrs=0; int addIncrs=0; for(j=0;j
                 
                  lenNum2;j++) { int multiTmp=(this->num1[i]-48)*(this->num2[j]-48)+incrs; incrs=multiTmp/10; int rest=multiTmp%10; int addTmp=(this->result[i+j]-48)+rest+addIncrs; addIncrs=addTmp/10; this->result[i+j]=addTmp%10+48; } this->result[i+j]+=addIncrs+incrs; } this->reverseNumber(this->result); return this->result;}int main(){ char a[]="12345678909876543210"; char b[]="12345678909876543210"; cout<
                  <
                   
                    <
                    <
                     
                      Mutiplicate(); cout<
                      
                       <
                       
                        >s;}