Calculating GPA: Find the Average

[magnifik]

i know this is a super easy program, but for some reason it's not working the way i want it to

// prompt user to enter several GPA's then find the average
// while the user's input is not the sentinel value, -1, add it to the sum
#include <iostream>

using namespace std;

int main(){
	double GPA = 0;
	double sum = 0;
	double count = 0;
	double average = sum / count;

	while (GPA != -1){
		cin >> GPA;
		sum += GPA;
		if (GPA != 1){
			count++;
		}
	}
	cout << average;
	return 0;
}

 

[Zryn]

For programs like this, its easy to create output statements for the value of variables as the math progresses. You can then imput simple numbers that you can calculate the program output value for on paper and compare them to the answer the program gives, then work backwards to find the error.

Where in your program does the 'average' variable get changed from its initialisation value of 'sum / count' to ... anything else ... before it is output ?

 

[xcvxcvvc]

First off, you are doing your average calculation before any input is given. In the declarations, put only "double average;" and after your while loop terminates, put "average = sum/count;"

Second, count should go up if GPA != -1, not if GPA != 1

third, (though this isn't ruining your program), I would make count an integer since it only ever accepts integer values. During the average calculation, the double divided by an integer will automatically convert the integer to a double to do double division and store that double in average.

 

[Math Is Hard]

Ditto what they said.

It's also probably not a good idea to initialize average to the value 0/0.

 

[DeeNos]

I understand how frustrating it can be when a program isn't working as expected. It's important to troubleshoot and identify the issue in order to find a solution. In this case, it seems like the program is not properly counting the number of GPAs entered, which is affecting the calculation of the average.

One possible solution could be to use a separate variable to keep track of the number of GPAs entered, rather than relying on the GPA variable. This way, the count will accurately reflect the number of GPAs entered, and the average calculation will be correct.

Another potential issue could be the use of the -1 as the sentinel value. It's important to make sure that the user is aware of this value and knows to enter it to end the program. Providing clear instructions and prompts can help avoid any confusion.

Overall, it's important to thoroughly test and debug the program to ensure it is functioning as intended. Making small adjustments and identifying any potential errors can help improve the program and make it more user-friendly.