Basic looping question confusion

[D0CHollywood]

The below code works fine, but I believe there is a cleaner way of coding it. I need the program to quit immediately if a negative value for age is entered. Thanks all!

  #include <iostream>
bool target_heart_rate_calc(int, int); //Func prototype for target heart rate calc, which returns bool
using namespace std;

int main()
{
   int age = 1, heart_bpm = 0; // Declare and initialize input variables
   bool within_heart_rate = 1;

   do
   {
      cout << "Enter your age, or enter a negative number to quit: ";
      cin >> age;
      if (age < 0) // If negative value for age is entered, program will exit
         break;
      else
      {

         cout << "Enter your heart beats per minute: ";
         cin >> heart_bpm;
         within_heart_rate = target_heart_rate_calc(age, heart_bpm);
         if (within_heart_rate)
            cout << "You are in your target heart rate. " << endl;
         else
            cout << "You are not in your target heart rate. " << endl;
      } 
   } while (age > 0);  // Loop will continue until a negative number for age is entered
  
     
   return 0;
}

bool target_heart_rate_calc(int age, int bpm) //function body
{
   bool within_target_heart_rate;
   double maximal_heart_rate = 0.0, calculated_target_heart_rate = 0.0;
   maximal_heart_rate = (220 - age) ;
   calculated_target_heart_rate = (bpm / maximal_heart_rate) * 100;
   if (calculated_target_heart_rate >= 60.0 && calculated_target_heart_rate <= 70.0)
      within_target_heart_rate = true;
   else
      within_target_heart_rate = false;

   return within_target_heart_rate;
}

[SECMoG1T]

I need the program to quit immediately if a negative value for age is entered
use a while loop instead

while(something>0) that way you wouldn't need any extra iteration

[D0CHollywood]

Thanks for the response andy. I changed it to the following code, but arent the while loop arguments useless anyway? By that I mean the if statement is the one that actually will break up the loop, not the while loop. Thanks for your help.

   
while (age > 0)
   {
      cout << "Enter your age, or enter a negative number to quit: ";
      cin >> age;
      if (age < 0) // If negative value for age is entered, program will exit
         break;
      else
      {

         cout << "Enter your heart beats per minute: ";
         cin >> heart_bpm;
         within_heart_rate = target_heart_rate_calc(age, heart_bpm); // Call heart rate calc function and pass age and bpm to it
         if (within_heart_rate) // If return value from function is true, output message to user
            cout << "You are in your target heart rate. " << endl;
         else // If return value from function is false, output message to user
            cout << "You are not in your target heart rate. " << endl;
      }

   }
     
   return 0;
}

[SECMoG1T]

Ooh i hadn't seen that, okay if you got that for control you could even replace the loop condition with a boolean literal while(true)

[D0CHollywood]

Got it. Thanks man!