CODEWITHSUNDEEP
c++
Andy Zheng
Andy Zheng

Reputation: 17

Function that will average out numbers that are not negative numbers

I am supposed to allow the user to enter non-negative numbers, and once a negative number is entered, the function should display the average of the proceeding non-negative numbers.

I am using XCode to do C++ work.

int Question6(){
    double nums;
    double totalnums = 0;
    int count = 0;

    cout << "Please enter the numbers that you like to be average that are non-negative:";
    cin >> nums;

    while (nums > 0){
        cout << "Please enter the numbers that you like to be average that are non-negative:";
        cin >> nums;
        totalnums += nums;
        count += 1;

        if (nums < 0){

            cout << "You have enterd a negative number so your average is:" << (totalnums/ count) << endl;

        }

    }

    return 0;
}

I have gotten the build to be successful but it always gives me a average with the negative number included. Is there a way to stop this from happening?

Upvotes: 0

Views: 120

Answers (2)

Daniel Jour
Daniel Jour

Reputation: 16156

A cleaner solution - with error checking - is to loop while you have valid input, and then decide what to do based on the sign of the input:

while (std::cin >> number)
{
  if (number >= 0)
  {
     // update values needed for average calculation
  }
  else
  {
     // calculate average, display
     break; // exit the while loop
  }
}
// Optionally: Check if loop exited due to read error or negative number
if (std::cin)
{
  // read a negative value
}
else
{
  // IO error (such as eof, no more numbers)
}

Upvotes: 1

Bogdan Doicin
Bogdan Doicin

Reputation: 2416

The problem is here:

 while (nums > 0)
   {
        cout << "Please enter the numbers that you like to be average that are non-negative:";
        cin >> nums;
        totalnums += nums;
        count += 1;

        if (nums < 0)
            {    
            cout << "You have enterd a negative number so your average is:" << (totalnums/ count) << endl;
            }

    }

The problem is the if instruction in the while loop. If you enter a negative number, it gets added to your totalnums+=nums instruction, because it's the next instruction after cin. After that, the while condition becomes false and the program exits the loop.

To fix your bug, check if nums<0 before you enter the while loop.

Upvotes: 3

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