inquiry about while loop structure

[elmoro15]

hello guys.. i just started studying while loop ..!

this is the first code i that i wrote.

#include <iostream>
using namespace std;
int main()
{
	int sum,i;
	i=0;
	sum=0;
	int num;
	int n;
	cout<<"enter the number of your marks"<<endl;
	cin>>n;
		
	while (i<n){
	cout<<"enter the value of ur marks"<<endl;
		cin>>num;

		sum=sum+num;
	
			i++;
	}
	double avg;

	cout<<"SUM="<<sum<<endl;
	cout<<"Avg="<<avg/sum;
}

the error is: it doesn't calculate the avearge..?!?!?!?
why??

[jlb]

And what was this error? Post the complete error messages exactly as they appear in your development environment along with the code that generated these errors.

[elmoro15]

it tells me that the variable avg is being used without being initialized..?!?

i did initialize it.!!??!?!?

[vlad from moscow]

And what do you want? The message of the compiler is clear enough.

[AbstractionAnon]

i did initialize it.!!??!?!?

Where?

[elmoro15]

line 21
.. i found..
the avg is wrong.. it isn't calculated like this.!

avg=sum/number of times.!!

should it be .. avg=sum/i or n?????? in my code

[AbstractionAnon]

should it be .. i or n?????? in my code

Which represents the number of marks?

[booradley60]

This code is functionally equivalent to what you posted in the original (logical errors and all). All I did was add a little whitespace and make more descriptive variable names. The logical error at your 'average' calculation really jumps out when more descriptive names are used.

#include <iostream>
using namespace std;
int main()
{
	int totalSumOfMarks, numberOfMarksIChecked;
	numberOfMarksIChecked=0;
	totalSumOfMarks=0;
	int theNextMark;
	int totalNumberOfMarks;
	cout<<"enter the number of your marks"<<endl;
	cin>>totalNumberOfMarks;
		
	while (numberOfMarksIChecked < totalNumberOfMarks){
	cout<<"enter the value of ur marks"<<endl;
		cin>> theNextMark;

		totalSumOfMarks= totalSumOfMarks + theNextMark;
	
			numberOfMarksIChecked++;
	}
	double averageMark;

	cout<<"SUM="<< totalSumOfMarks <<endl;
	cout<<"Avg="<< averageMark/totalSumOfMarks;
}

[agnophilo]

You declared the variable i but you never initialized it (gave it an initial value) so when the program goes to check if it's less than n it has nothing to do (no value to check), thus you get a compiling error.

[agnophilo]

Next time you get an error saying you didn't initialize something, if the answer isn't immediately obvious google c++ initialize (or whatever the error message or terms are) for clues.

I'm surprised nobody answered this.