# 大数乘法

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# include<string.h>

using namespace std;

int multi(int num1, int size1, int* num2, int size2){

``int size = size1 + size2; int* ret = new int[size]; int  i   = 0;  memset(ret, 0, sizeof(int) * size);   for(i = 0; i<size2; ++i){      int k = i;     for(int j = 0; j < size1; ++j){          ret[k++] += num2[i] * num1[j];                 }   }    for (i = 0; i < size; ++i){      if(ret[i] >= 10){          ret[i+1] += ret[i]/10;         ret[i]   %= 10;     } }    return ret;``

}

int main(int argc, char** argv) {

``char digit1[100]; char digit2[100];  cin >> digit1 >> digit2;  int size1 = strlen(digit1); int size2 = strlen(digit2);  int* num1 = new int[size1]; int* num2 = new int[size2];  int* currentDigit1 = new int[size1]; int* currentDigit2 = new int[size2];  for(int j = 0, jj = size1 - 1; j < size1; j++, jj--){      num1[jj] = digit1[j] - '0';  }  for(int k = 0, kk = size2 - 1; k < size2; k++, kk--){      num2[kk] = digit2[k] - '0';  }   int* ret = multi(num1, size1, num2, size2);  cout<<"求得的乘积为:"<<endl;  for(int i = size1+size2-2; i >= 0 ; i--){      cout << ret[i];  }  delete[] ret; return 0;``

}