C语言实现高精度加法

//author   summer_awn
//date    2017/6/20
 
#include<iostream>
#include<time.h>
 
#define lenth_a 200
#define lenth_b 200
 
using namespace std;
 
//计算a+b
void main() {
 
 srand((unsigned)time(NULL));
 
 int * a = new int[lenth_a];//数组a            ******
 
 for (int i = 0; i < lenth_a; ++i) {
 
  a[i] = rand() % 10;
 
 }
 
 cout << "a=";
 for (int i = lenth_a - 1; i >= 0; --i) {//输出a
  cout << a[i];
 }
 cout << endl;
 cout << endl;
 
 int * b = new int[lenth_b];//数组b            ******
 
 for (int i = 0; i < lenth_a; ++i) {
 
  b[i] = rand() % 10;
 
 }
 
 cout << "b=";
 for (int i = lenth_b - 1; i >= 0; --i) {//输出b
  cout << b[i];
 }
 cout << endl;
 cout << endl;
 
 
 
 int lenth_result;//结果的长度en
 
 if (lenth_a > lenth_b) lenth_result = lenth_a + 1; 
 else lenth_result = lenth_b + 1;//通过一个判断来确定结果的长度
 
 
 int * a2 = new int[lenth_result];//a2***********
 
 int * b2 = new int[lenth_result];//b2***********
 
 memcpy(a2, a, sizeof(int)*lenth_a);//
 
 memset(a2 + lenth_a, 0, sizeof(int)*(lenth_result - lenth_a));
 
 memcpy(b2, b, sizeof(int)*lenth_b);
 
 memset(b2 + lenth_b, 0, sizeof(int)*(lenth_result - lenth_b));
 
 delete(a);
 delete(b);
 
 int * result = new int[lenth_result];//result*********
 
 result[0] = a2[0] + b2[0];
 
 for (int i = 1; i < lenth_result - 1; ++i) {
 
  result[i] = a2[i] + b2[i] + result[i - 1] / 10;
 
  result[i - 1] = result[i - 1] % 10;
 }
 
 result[lenth_result - 1] = result[lenth_result - 2] / 10;
 
 result[lenth_result - 2] = result[lenth_result - 2] % 10;
 
 delete(a2);
 delete(b2);
 
 cout << "结果=";
 for (int i = lenth_result - 1; i >= 0; --i) {
  cout << result[i];
 }
 cout << endl;
 
 system("pause");
 
 delete(result);
}