Write a program that can be used to gather statistical data about the number of

Question

Write a program that can be used to gather statistical data about the number of movies college students see in a month. The program should perform the following steps:

A) Ask the user how many students were surveyed. An array of integers with this many elements should then be dynamically allocated.

B) Allow the user to enter number of movies each student saw into the array.

C) Calculate and display the average, median, and mode of the values entered. (Use the function you wrote in Problems 8 and 9 to calculate the median and mode.)

Input Validation: Do not accept negative numbers for input.

Explanation / Answer

#include <iostream>
using namespace std;
void getinfo(int*, int);
void sort(int [], int);
double average(int*, int);
double median(int*, int);
int   get_mode(int*, int);
int main()
{ int*array;
   int num;     
   int mode,i,range;
    float avg;
    cout<<"enter number of students? ";
    cin>>num;
   while(num<=0)
    {cout<<"Invalid Entry ";
    cout<<"enter number of students? ";
    cin>>num;
    }
array=new int[num];
      getinfo(array, num);
   cout<<" The array is: ";
   for(i=0;i<num;i++)
       cout<<"student "<<i+1<<" saw "<<*(array+i)<<" movies. ";
   sort(array, num);
   cout<<"the median is "<<median(array, num) << endl;
   cout<<"the average is "<<average(array, num) << endl;
   mode=get_mode(array, num);
   if(mode<0)
         cout<<"There is no mode. ";
   else
         cout<<"The mode is " << mode << endl;
delete [] array;
system("pause");
return 0;
}
void getinfo(int a[], int n)
{int i;
   for(i=0;i<n;i++)
      {cout<<"How many movies did student "<<(i+1)<< " see? ";
       cin >> a[i];
        while(a[i]<0)         
         {cout<<"Invalid entry, must be >= 0 ";
         cout<<"How many movies did student "<<(i+1)<< " see? ";
          cin>>a[i];
          }
      }
}
double average(int a[], int num)
{ int tot=0,i;
   double avg;
   for(i=0;i<num; i++)
       tot+=a[i];
   avg=(double)tot/num;
   return avg;
}

void sort(int a[], int n)
{ int i,j,t;
for(i=0;i<n-1;i++)
     for(j=i;j<n;j++)
        if(a[i]>a[j])
           {t=a[i];
           a[i]=a[j];
           a[j]=t;
           }
}
double median(int* a, int n)
{ int m1,m2;
   if (n%2==0)
        {m1=n/2;
         m2=(n/2)-1;
         return((*(a+m1)+*(a+m2))/2.);
        }
   else
       
   return *(a+(n/2));
}
int get_mode(int* a, int n)
{
   int* count,most,index,i,j;
   count= new int[n];
   for (i= 0;i< n;i++)
         count[i] = 0;
   for(i=0;i<n;i++)
      {for(j=0;j<n;j++)
           {if(*(a+j)==*(a +i))
              (*(count+i))++;
            }
      }
   most=*count;
   index=0;
   for (i=1;i<n;i++)
      {if (*(count+i) >most)
      {most=*(count+i);
       index=i;
      }
   }
   if (most == 1)
         return -1;
   else
         return *(a+index);
}

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