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Trouble with Class and Vector.

jmazorra (7)
Hello everyone:

this is a class project, so I am looking for some guidance. The following program is supposed to print out a bank statement listing all deposits, withdrawls, and balance and compute interest. All is well except I keep getting an error:

 
 
error LNK2019: unresolved external symbol "public: __thiscall BankTrans::BankTrans(void)" (??0BankTrans@@QAE@XZ) referenced in function "public: void __thiscall Statement::read(void)" (?read@Statement@@QAEXXZ)


I think my problem is in the line 40: void BankTrans::read() const{}

but I can't figure out what I am doing wrong. I've been at it for 2 days and was able to narrow it down to that line, but I am stuck. Any guidance will be surely appreciated.

Thank you

Here is my code



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#include <iostream>
#include <string>
#include <vector>
using namespace std; 

int MONTH_DAY = 30; 


class BankTrans { 

public: 
	BankTrans(); 
	BankTrans( int i_day, double i_amount, string i_description); 
	void read() const; 
	void print(); 
	int get_day() const; 
	double get_amount() const; 

private: 
	int input_day; 
	double input_amount; 
	string input_description; 
}; 

BankTrans::BankTrans (int i_day, double i_amount, string i_description){ 
	input_day = i_day; 
	input_amount = i_amount; 
	input_description = i_description; 
}

int BankTrans::get_day() const{ 
	return input_day; 
} 

double BankTrans::get_amount() const{ 
	return input_amount; 
} 

void BankTrans::read() const{ 
	
} 

void BankTrans::print() { 
	cout << "DAY " << "AMOUNT " << "DESCRIPTION " <<endl; 
	cout <<input_day<< " " << input_amount <<" "<< input_description <<" " <<endl; 
} 





class Statement{ 
public: 
	Statement(); 
	void read(); 
	void print(); 
	void compute_bal(); 
	double get_avg_day_bal(); 
	double get_min_day_bal(); 


private: 

	vector <BankTrans> transactions;
	vector <double> day_bals; 

}; 

Statement::Statement(){ 

} 

void Statement::read(){
	cout << "Use format DAY AMOUNT DESCRIPTION to enter your transaction: " << endl; 
	bool more = true; 
	while (more); 
	{ 
		BankTrans new_trans; 
		new_trans.read(); 
		if (cin.fail()) 
			more = false; 
		else 
			transactions.push_back(new_trans); 

	} 
	compute_bal(); 
} 


void Statement::compute_bal(){ 
	int day; 
	int i = 0; 
	double balance = 0; 
	
	for (day = 1; day <= MONTH_DAY; day++) { 
		while (i < transactions.size() && transactions[i].get_day() == day) 
		{ 
			balance = balance + transactions[i].get_amount(); 
			i++; 
		} 
		day_bals.push_back(balance); 
	
	} 
} 

double Statement::get_avg_day_bal() { 
	int day; 
	double sum_of_bals = 0; 
	for (day = 0; day < day_bals.size(); day++) 
		sum_of_bals = sum_of_bals + day_bals[day]; 
	return sum_of_bals / MONTH_DAY; 

} 

double Statement::get_min_day_bal() { 
	int day; 
	double min_bal = day_bals[0]; 
	for (day = 1; day < day_bals.size(); day++) 
		if (day_bals[day] < min_bal) 
			min_bal = day_bals[day]; 
	return min_bal; 

} 

void Statement::print() { 
	int day; 
	int i = 0; 
	
	for (day = 1; day <= MONTH_DAY; day++) 	{ 
		
		cout << "DAY: " << day << "BALANCE: " << day_bals[i - 1] << endl; 
		while (i < transactions.size() && transactions[i].get_day() == day) 
		{ 
			transactions[i].print(); 
			i++; 
		} 
	} 
	
	
	const double INTEREST = 0.005; 
	cout << "The minimum daily interest balance is: " << get_min_day_bal() * INTEREST << endl; 
	cout << "The average daily balance with interest is: " << get_avg_day_bal() * INTEREST << endl; 
} 

int main() 

{ 
	system("Pause");
	return 0; 

}
JLBorges (13770)
The error diagnostic: unresolved external symbol "... BankTrans::BankTrans(void)"
tells you what the problem is.

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class BankTrans { 

public: 
	BankTrans(); // *** this has not been defined
// ....
Null (957)
You didn't implement BankTrans::BankTrans() function.
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class BankTrans { 

public: 
	BankTrans(){/* initialize variables here, if you need*/}; 
// ...
}

should work
Rechard3 (284)
there you got it, as did Null say, you just have to "define" the default constructor for the BankTrans class, just give it any definition and it should work like charm.
you can replace the BankTrans() declaration with this:

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        .
        .
        .
class BankTrans      { 

public: 
	BankTrans() {}
        .
        .
        .
jmazorra (7)
Thank you,

I am new to C++ and struggling a bit with function and classes. I thought I implemented the BankTrans:BankTrans() function on line 26? Did I not do it correctly?
JLBorges (13770)
These are two different constructors:
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class BankTrans { 

public: 
	BankTrans(); // constructor one
	BankTrans( int i_day, double i_amount, string i_description); // constructor two
        // ...


You had a definition for constructor two; but didn't have one for constructor one

See 'Overloaded functions' in http://www.cplusplus.com/doc/tutorial/functions2/
Last edited on
jmazorra (7)
Thank you all, this was extremely helpful
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