Question

Keep getting these errors while trying to compile an c++ class program.

testStock.cpp: In function ‘int main()’: testStock.cpp:8: error:
‘Stock’ was not declared in this scope testStock.cpp:8: error:
expected ;' before ‘first’ testStock.cpp:9: error: ‘first’ was not
declared in this scope testStock.cpp:12: error: expected;’ before
‘second’ testStock.cpp:13: error: ‘second’ was not declared in this
scope

stock.h

#ifndef STOCK_H
#define STOCK_H
using namespace std;

class Stock
{
 private:
  string symbol;
  string name;
  double previousClosingPrice;
  double currentPrice;
 public:
  Stock(string symbol, string name);
  string getSymbol() const;
  string getName() const;
  double getPreviousClosingPrice() const;
  double getCurrentPrice() const;
  double changePercent();
  void setPreviousClosingPrice(double);
  void setCurrentPrice(double);
};

#endif

stock.cpp

#include <string>
#include "stock.h"

Stock::Stock(string symbol, string name)
{
  this->symbol = symbol;
  this->name = name;
}

string Stock::getSymbol() const
{
  return symbol;
}

string Stock::getName() const
{
  return name;
}

void Stock::setPreviousClosingPrice(double closing)
{
  previousClosingPrice = closing;
}

void Stock::setCurrentPrice(double current)
{
  currentPrice = current;
}

double Stock::getPreviousClosingPrice() const
{
  return previousClosingPrice;
}

double Stock::getCurrentPrice() const
{
  return currentPrice;
}

double Stock::changePercent() 
{
  return ((currentPrice - previousClosingPrice)/previousClosingPrice) * 100;
}

testStock.cpp

#include <string>
#include <iostream>
#include "string.h"
using namespace std;

int main()
{
  Stock first("aapl", "apple");
  cout << "The stock symbol is " << first.getSymbol() << " and the name is " << first.getName() << endl;
  first.setPreviousClosingPrice(130.0);
  first.setCurrentPrice(145.0);
  Stock second("msft", "microsoft");
  second.setPreviousClosingPrice(30.0);
  second.setCurrentPrice(33.0);
  first.changPercent();
  second.changePercent();
  cout << "The change in percent for " << first.getName << " is " << first.changePercent() << endl;
  cout << "The change in percent for " << second.getName << " " << second.getSymbol() << " is " << second.changePercent() << endl;

  return 0;
}

Im sure its something obvious but its only my second class program.

Answer 1

Compiler tells you “‘Stock’ was not declared in this scope “. So you should ask yourself “Where is ‘Stock’ declared?” and you should be able to answer it: “It’s declared in stock.h“.

And “Why compiler doesn’t know that ‘Stock’ is declared in stock.h?” Because you haven’t included it. So as it was mentioned here already, #include "stock.h" is the solution.

Hope you will spend more time reading compilers errors / warnings and also more time trying to understand them 😉