Question

So the variable hoursWorked is not initialized. But how am I supposed to initialize it if I want it to equal whatever the user stores in it? For example I want hoursWorked to be whatever any person outputs in it in cin. Here is my code:

#include <iostream>

using namespace std;

int main () 
{
   //Declare Variables
   double hoursWorked;
   double payRate;
   double incomeBeforeTax;

   payRate = 15;
   incomeBeforeTax = payRate * hoursWorked;

   cout << "Enter hours worked: ";
   cin >> hoursWorked;
   cout << endl;
   cout << incomeBeforeTax << endl; 

   return 0;
}

Answer 1

The calculation of incomeBeforeTax which references hoursWorked needs to occur after you initialize it by reading from cin. Move that line after cin >> hoursWorked; and it will work:

payRate = 15.0;

cout << "Enter hours worked: ";
cin >> hoursWorked;

incomeBeforeTax = payRate * hoursWorked;

cout << endl;
cout << incomeBeforeTax << endl;

C++, like most procedural languages evaluates your code in the order in which it is written. That is, incomeBeforeTax = payRate * hoursWorked; assigns a value to incomeBeforeTax based on the current values of payRate and hoursWorked. These must be defined and initialized before the assignment is performed. That is what cin >> hoursWorked does.

On a side note, double variables are best initialized with double literals so add .0 to the value.