C++ 高精度

高精度加法

#include<stdio.h>
#include<iostream>
#include<memory.h>
#include<cstring>
#include<algorithm>
using namespace std;
int main(int argc, char const *argv[])
{
  char a1[100], b1[100];
  int a[100], b[100], c[100];
  int lena1, lenb1;
  memset(a, 0, sizeof(a));
  memset(b, 0, sizeof(b));
  memset(c, 0, sizeof(c));
  gets(a1);
  gets(b1);
  //scanf("%s%s", &a1, &b1);
  lena1 = strlen(a1);
  lenb1 = strlen(b1);
  for(int i = 0; i < lena1; ++i)    //将char转化成int，数组倒置
    a[lena1-i-1] = (int)a1[i] - '0';
  for(int i = 0; i < lenb1; ++i)
    b[lenb1-i-1] = (int)b1[i] - '0';
  int lenc = 0, x = 0;    // x记录进位
  while(lenc <= lena1 || lenc <= lenb1)
  {
    c[lenc] = a[lenc] + b[lenc] + x;
    x = c[lenc]/10;
    c[lenc] %= 10;
    lenc++;
  }
  c[lenc] = x;
  if(c[lenc] == 0)
  {
    lenc--;    //判断前导0
  }
  for(int i = lenc-1; i >= 0; --i)
    printf("%d",c[i]);
  ret