保存在String Object中的HugeInteger对象的位数

我正在研究一个巨大的整数问题，我必须创建一个HugeInteger类，其中数字将存储在字符串对象中，而不是固定(静态)大小的无符号短裤数组。我被困在如何实现这一点。当我运行程序时，我为我的HugeInteger对象输入值，但是之后什么也没有显示。我很感激你的帮助。提前感谢。

下面是我到目前为止所拥有的源代码。

HugeInteger.h

#include <iostream>
#include <array>
#include <string>
class HugeInteger
{
    // need to offer friendship to these 2 functions
    friend std::istream & operator >> (std::istream & src, HugeInteger & value);
    friend std::ostream & operator << (std::ostream & dest, const HugeInteger & value);
public:
    //ctor that converts a "long long" into a HugeInteger
    HugeInteger(long long value = 0LL); //0LL is constant literal value 0
    //   of type long long
    //ctor that converts a string into a HugeInteger
    HugeInteger( char *str);
    //Convert a string into a HugeInteger
    void input( char *str);
private:
    bool negative;  // will be true if number is negative
    std::string hugeInt; // each digit is stored in a string object
};
//overloads the << and >> operators for the HugeInteger class
std::istream & operator >> (std::istream & src, HugeInteger & value);
std::ostream & operator << (std::ostream & dest, const HugeInteger & value);

HugeInteger.cpp

#include "HugeInteger.h"
#include <iostream>
using namespace std;
// ctor converts a long long into a HugeInteger
HugeInteger::HugeInteger(long long value)
{
    // set all MaxDigit digits to zero to start
    this->negative = false;
    if (value < 0LL){ // 0LL is constant literal 0 of type long long
        this->negative = true;
        value = -value; // make the value positive                  
    }
    unsigned int i = 0;
    for (; i < hugeInt.size(); i++)
    {
        this->hugeInt[i] = '0';
    }
    this->hugeInt[i] = '';
    // convert individual digits of input value into a HugeInteger
    for (unsigned int j = hugeInt.size() - 1; j >= 0 && value != 0LL; j--)
    {
        short result = value % 10;
        char c = (char)result;
        this->hugeInt[j] = c;
        value /= 10;
    }
    // test to make sure that HugeInteger was able to contain value
    if (value != 0LL){
        *this = 0LL; // set to -0, to signal overflow
        this->negative = true; //   Possibly should increase value assigned
    }                          //   to MaxDigit to fix this problem.
}
// converts string into a HugeInteger object
HugeInteger::HugeInteger(char *str)
{
    this->input(str); //See HugeInteger::input() method below
}
void HugeInteger::input( char *str)
{
    // assume positive for now
    this->negative = false;
    // init. to all zeros first
    unsigned int i = 0;
    cin.getline(str, sizeof str);
    cin.sync();
    cin.clear();
    while (i < strlen(str) - 1)
    {
        if (isdigit(str[i]))
        {
            this->hugeInt[i] = str[i];
            i++;
        }
    }
istream & operator>>(istream & input, HugeInteger & value)
{
    char inputString[1002];
    input >> inputString;
    value.input(inputString);
    return input;
}
ostream & operator << (ostream & output, const HugeInteger & value)
{
    // find first non-zero digit
    unsigned int i = 0;
    while (i < value.hugeInt.size()){
        if (value.hugeInt[i] != '0'){
            break;
        }
        ++i;
    }
    // if all zeros, just output a single 0
    if (i == 40)
    {
        cout << '0';
        return output;
    }
    // check if we need to ouput a negative sign
    if (value.negative){
        cout << '-';
    }
    // output remaining digits
    for (; i < value.hugeInt.size(); i++)
    {
        cout << value.hugeInt[i];
    }
    return output;
}

MainProg.cpp

#include "HugeInteger.h" // include definiton of class HugeInteger
using namespace std;
    int main()
    {
        HugeInteger A, B, C, D;
        // input value for A & B
        cout << "****** Test << & >> operators ******nn";
        cout << "Input values for A and B: ";
        cin >> A >> B;
        cout << "nA = " << A << "nB = " << B;
    system("pause");
        return 0;
    } // end main