mm.., hello. First, i'm kinda new to this... kinda, anyway, i'm supposed to write a prog that handles large numbers, like 200 digits long, by storing them in a string of characters. it's supposed to have a class with functions for all the mathematical operations, reading, and writing, maybe into a text file. i found a prog that does this, written by someone else, but now i want to rewrite it so i can understand how it works.
The code below is supposed to store and show a number like this on screen. It's made of pieces from the one i found. i managed to eliminate compile errors but it bogs down when i try to run it.

gives these errors:
try1.obj : error LNK2001: unresolved external symbol "public: __thiscall L_No::L_No(int)" (??0L_No@@QAE@H@Z)
Debug/try1.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.

can anyone help make it work?... if i have this i think i can make the rest alone:-/

#include <string>
#include <vector>
#include <iostream>

using namespace std;


class L_No
{
public:
	//Default Constructor
	L_No() : Sign_of_no(1) { No.push_back(0); }
	//Constructor From a Number
	L_No(int iNumber);
	//Constructor From a String
	L_No(string const& rostrNumber);
protected:
	//Build from unsigned long
	static void Build(unsigned uN, vector<char>& rvN);
	//Build from string
	static void Build(string const& rostrNumber, vector<char>& rvN);
	//Cleaning
	static void Clean(vector<char>& rvN);
	//Comparison Function
public:
	//Transform to a string
	string ToString() const;
private:
	//-1 - Negative, +1 - Positive or zero
	char Sign_of_no;
	vector<char> No;
};

//Build from unsigned long
void L_No::Build(unsigned uN, vector<char>& rvn)
{
	rvn.clear();
	if(0 == uN)
		rvn.push_back(0);
	else
		for( ;uN>0; )
		{
			rvn.push_back(uN % 10);
			uN /= 10;
		}
}

//Build from string
void L_No::Build(string const& rostrNumber, vector<char>& rvn)
{
	rvn.clear();
	for(int i=rostrNumber.size()-1; i>=0; i--)
	{
		if(rostrNumber[i]<'0' || rostrNumber[i]>'9')
			break;
		else
			rvn.push_back(rostrNumber[i]-'0');
	}
	Clean(rvn);
}

//Cleaning
void L_No::Clean(vector<char>& rvn)
{
	//Eliminate all leading 0s
	vector<char>::iterator it = rvn.end();
	while(it != rvn.begin())
	{
		it--;
		if(*it != 0)
			break;
	}
	rvn.erase(it+1, rvn.end());
}


L_No::L_No(string const& rostrNumber)
{
	//Eliminating leading and trailing blanks
	int iEnd;
	iEnd = rostrNumber.size()-1;
	for(; (rostrNumber[iEnd]==' ')&&(iEnd>=0); iEnd--)
		;
	if(iEnd < 0)
	{
		Sign_of_no = 1;
		Build(0, No);
		return;
	}
	int iBeg;
	for(iBeg=0; ' '==rostrNumber[iBeg]; iBeg++)
		;
	string ostrNumber = rostrNumber.substr(iBeg, iEnd-iBeg+1);
	iBeg = 0;
	if('-' == ostrNumber[0])
	{
		Sign_of_no = -1;
		iBeg = 1;
	}
	else
		Sign_of_no = 1;
	Build(ostrNumber.c_str()+iBeg, No);
}

//Transform to a string
string L_No::ToString() const
{
	if(0 == No.size())
		return "0";
	string ostr;
	if(-1 == Sign_of_no)
		ostr += '-';
	vector<char>::const_reverse_iterator rIter = No.rbegin();
	for(; rIter != No.rend(); rIter++)
		ostr += *rIter+'0';
	return ostr;
}
int main()
{
	L_No oLN1 = L_No(1000000);
	cout<<oLN1.ToString()<<endl;
	return 1;
}

try1.obj : error LNK2001: unresolved external symbol "public: __thiscall L_No::L_No(int)"

In the class declaration you say:

public:
L_No(int iNumber);

But there's no definition of this constructor.
So add:

L_No::L_No(int iNumber) 
{
	// do stuff with int iNumber
}

And your code should compile.

if i have this i think i can make the rest alone

Ok. If you say so.
Have fun :icon_mrgreen:

i'm a beginer but this mistake is embarrassing:icon_redface:
thanks, it works now

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