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C++ help with student array problem

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Join Date: Jun 2005

Posts: 92

Reputation: djbsabkcb is an unknown quantity at this point

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djbsabkcb

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Junior Poster in Training

C++ help with student array problem

Jul 22nd, 2005

I must ask user number of students who took test, then create a dynamic array and then get the scores for each student. Then calculate the sum,average of the scores. My problem is that once it calculates it continues to ask user for student scores. I am confused with this while loop. Below is my source code. Any ideas?

#include <iostream>
#include <cmath>
#include <cstdlib>

using namespace std;

int main()
{

double grade= 0;
double sum = 0;
int count = 0;
double avg_score = 0;

cout << " Enter the number of students who took test : " ;
int num_students = 0;
cin >> num_students;
// cout << endl;

// double* p = new double[num_students];
while(true){
if (num_students== 0 || num_students == -1)
{

cout << " Enter a postive value please!" << endl;
cout << " Enter the number of students who took tests: ";
cin >> num_students;
cout << endl;
} // end of if statement

double* p = new double[num_students];

for (int i = 1; i <= num_students; i++)
{
cout << " Enter grade for Student " << i << ":" ;
cin >> grade;

p[i] = grade;
cout << p[i]<< endl;
sum += grade;
++count;
} // end of for loop
delete []p;

avg_score = sum / count;

cout << " The average of the test scores is " << avg_score << endl;
cout << " The sum of the test scores is " << sum << endl;
} // end of while loop
return 0;
}

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Join Date: Feb 2005

Posts: 466

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winbatch

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Posting Pro in Training

Re: C++ help with student array problem

Jul 22nd, 2005

You could just put a break; at the end of your while loop, or the better way would be to change the while loop to only ask for the information while num_students < 1. (Then you just do the for loop and exit). Also, be careful mixing your int's and double's for the same variable.

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#include <iostream>
#include <cmath>
#include <cstdlib>
 
using namespace std;
int main()
{
double grade= 0;
double sum = 0;
int count = 0;
double avg_score = 0;
cout << " Enter the number of students who took test : " ;
double num_students = 0;
cin >> num_students;
while (num_students < 0 )
{
	   cout << " Invalid Value! ";
		cout << " Enter the number of students who took test: ";
		cin >> num_students;
		cout << endl;
} 
double* p = new double[num_students];
 
for (double i = 1; i <= num_students; i++)
{
		cout << " Enter grade for Student " << i << ":" ;
		cin >> grade;
 
		p[i] = grade;
		cout << p[i]<< endl;
		sum += grade;
		++count;
} // end of for loop
delete []p;
avg_score = sum / count;
 
cout << " The average of the test scores is " << avg_score << endl;
cout << " The sum of the test scores is " << sum << endl;
return 0;
}
#include <iostream>
#include <cmath>
#include <cstdlib>
 
using namespace std;
int main()
{
double grade= 0;
double sum = 0;
int count = 0;
double avg_score = 0;
cout << " Enter the number of students who took test : " ;
double num_students = 0;
cin >> num_students;
while (num_students < 0 )
{
	   cout << " Invalid Value! ";
		cout << " Enter the number of students who took test: ";
		cin >> num_students;
		cout << endl;
} 
double* p = new double[num_students];
 
for (double i = 1; i <= num_students; i++)
{
		cout << " Enter grade for Student " << i << ":" ;
		cin >> grade;
 
		p[i] = grade;
		cout << p[i]<< endl;
		sum += grade;
		++count;
} // end of for loop
delete []p;
avg_score = sum / count;
 
cout << " The average of the test scores is " << avg_score << endl;
cout << " The sum of the test scores is " << sum << endl;
return 0;
}