尝试写了一个高精度小数乘法，遇到了很奇怪的情况。代码里没有随机生成的部分，但是每次输出的结果都不同？完全不能理解，求大佬解答。以下是代码，用的Dev C++ 5.11

#include<iostream>
#include<cmath>
#include<cstring>
using namespace std;
const int max_integer = 100, max_decimals = 100;

class Float
{
	public:
		//构造函数 0 
		Float() {}
		//构造函数 1 
		Float(char input[])
		{
			int i = -1, j = -1;
			bool deci_flag = false; 
			for (unsigned int k=0; k < strlen(input); k++)
			{	
				
				if (input[k] == '.')
					deci_flag = true;
				else
				{	if (!deci_flag && input[k] != '\0')
						integer[++i] = input[k];
					else if (j <= max_decimals - 3)
						decimals[++j] = input[k];
				}
			}
		}
		//友元函数声明
		friend ostream& operator << (ostream&, Float);
		friend Float operator + (Float, Float);
		friend Float operator * (Float, Float);
			friend void operator * (Float&, char);
		
	private:
		char integer[max_integer] = {'0'}; 
		char decimals[max_decimals] = {'0'};
};
//重载流插入运算符
ostream& operator << (ostream &output, Float input)
{
	output<<input.integer<<'.'<<input.decimals;
	return output;
} 
//加法
Float operator + (Float input_1, Float input_2)
{
	Float output;
	char a2[max_decimals], b2[max_decimals];
	strcpy(a2, input_1.decimals), strcpy(b2, input_2.decimals);
	//小数加法 
	int calt;
	bool jinwei_2[max(strlen(a2), strlen(b2)) + 1] = {false};
	for (int i = max(strlen(a2), strlen(b2)) - 1; i>=0; i--)
	{	if (a2[i] == '\0' || b2[i] == '\0')
			a2[i] = a2[i] + b2[i];
		else
		{	
			calt = a2[i] + b2[i] - '0'*2 + jinwei_2[i+1];
			a2[i] = calt % 10 + '0';
			jinwei_2[i] = calt / 10;
		} 
	} 
	//整数加法 
	char c[max_integer] = {'\0'};
	char a1[max_integer], b1[max_integer];
	if (strlen(input_1.integer) > strlen(input_2.integer))
	{	strcpy(a1, input_1.integer);
		for (unsigned int i=0; i < strlen(input_1.integer) - strlen(input_2.integer); i++)
			c[i] = '0';
		strcat(c, input_2.integer);
		strcpy(b1, c);
	}
	else
	{	strcpy(a1, input_2.integer);
		for (unsigned int i=0; i < strlen(input_2.integer) - strlen(input_1.integer); i++)
			c[i] = '0';
		strcat(c, input_1.integer);
		strcpy(b1, c);
	}
	bool jinwei_1[strlen(a1)+1] = {false};
	jinwei_1[strlen(a1)] = jinwei_2[0];
	for (int i = strlen(a1) - 1; i>=0; i--)
	{	calt = a1[i] + b1[i] - '0'*2 + jinwei_1[i+1];
		a1[i] = calt % 10 + '0';
		jinwei_1[i] = calt / 10; 
	}
	//赋值
	strcpy(output.decimals, a2);
	if (jinwei_1[0] == false)
		strcpy(output.integer, a1);
	else
	{	output.integer[0] = '1';
		strcat(output.integer, a1);
	}
	return output;
}
//单位乘法
void operator * (Float &input, char mult)
{
	if (mult == '0')
	{	Float zero;
		input = zero;
		return; 
	} 
	int calt;
	int jinwei_2[strlen(input.decimals)+1] = {0};
	for (int i = strlen(input.decimals) - 1; i>=0; i--)
	{	calt = (input.decimals[i] - '0') * (mult - '0') + jinwei_2[i+1];
		input.decimals[i] = calt % 10 + '0';
		jinwei_2[i] = calt / 10;
	}
	int jinwei_1[strlen(input.integer) + 1] = {0};
	jinwei_1[strlen(input.integer)] = jinwei_2[0];
	char store[max_integer] = {'\0'};  
	for (int i = strlen(input.integer) - 1; i>=0; i--)
	{	calt = (input.integer[i] - '0') * (mult - '0') + jinwei_1[i+1];
		store[i] = calt % 10 + '0';
		jinwei_1[i] = calt / 10;
	}
	if (jinwei_1[0] == 0)
		strcpy(input.integer, store);
	else
	{	char trans[max_integer] = {char(jinwei_1[0] + '0')};
		strcat(trans, store);
		strcpy(input.integer, trans);
	}
} 
//乘法
Float operator * (Float input_1, Float input_2)
{
	Float output; 
	//取出 input1的数 
	char connect[max_integer + max_decimals] = {'\0'};
	strcpy(connect, input_1.integer);
	strcat(connect, ".");
	strcat(connect, input_1.decimals);
	int point; char exchange;
	char move[max_integer + max_decimals]; 
	//整数部分乘法 
	for (int i = strlen(input_2.integer) - 1; i>=0; i--)
	{	strcpy(move, connect);
		point = strlen(input_1.integer);
		for (unsigned int j=0; j < strlen(input_2.integer) - 1 - i; j++)
		{	if (move[point + 1] == '\0')
				move[point + 1] = '0';
			exchange = move[point];
			move[point] = move[point + 1];
			move[point + 1] = exchange;
			point++;
		} 
		Float *add = new Float(move);
		*add * input_2.integer[i];
		output = output + *add;
		delete add; 
	}
	return output;
} 
int main()
{	

	char n1[] = "0.1212", n2[] = "10";
	Float a(n1), b(n2), c;
	cout<<a*b<<'*';

	return 0;
}