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#include <iostream>
#include <iomanip>
#include <cmath>
using namespace std;
//file level scope
const int columns = 4;
const int nColumns = 20;
//prototype for 2d array
void showNamesAndScores(int scores[][columns], char names[][nColumns], int);
//calcAvg
double calcAvg(int X[][columns], int);
//studentAvg
char studentAvg(int X[][columns], int);
//deviation
void deviation(int X[][columns], double Y[][columns], int, double);
//variance
void variance(double Y[][columns],int);
int main()
{
//declare rows & columns
const int rows = 5;
//declare 2d array
int scores[rows][columns];
char names[rows][nColumns];
//populate 2d array
for(int i=0; i<rows ;i++)
{
cout<<"Enter Name of student"<<i+1<<": ";
cin>>names[i];
cout<<endl;
}
for(int i=0; i<rows; i++)
{
cout<<"Enter "<<columns<<" scores for row "<<i+1<<": ";
for (int j=0; j<columns; j++)
{
cin>>scores[i][j];
}
cout<<endl;
}
//display scores with function
showNamesAndScores(scores, names, rows);
//display avg
double avg = calcAvg(scores, rows);
deviation(scores, devi, rows, avg); //error: 'devi' not declared in this scope. ???
cout<<"Class Avg: "<<avg<<endl;
variance(devi,rows); //error: 'devi' not declared in this scope. ???
}//endmain
//defines a function to accept 2d array
void showNamesAndScores(int scores[][columns], char names[][nColumns], int rows)
{
for(int i=0; i<rows; i++)
{
cout<<names[i];
cout<<setw(15);
for(int j=0; j<columns; j++)
{
cout<<scores[i][j]<<" ";
}
cout<<endl;
}
}//end names and scores
//calcAvg
double calcAvg(int X[][columns], int s)
{
double a;
double sum = 0;
for(int i=0; i<s; i++)
{
for(int j=0; j<columns; j++)
{
sum += X[i][j];
}
}
a = sum/(s*columns);
return a;
}//endcalcAvg
//studentAvg
char studentAvg(int scores[][columns], int rows)
{
int sum = 0;
char grade;
for(int j=0; j<columns; j++)
{
sum += scores[rows][j];
}
double avg = sum/rows;
cout<<"avg"<<avg;
if(avg >= 90)
grade = 'A';
else if(avg >= 80 && avg < 90)
grade = 'B';
else if(avg >= 70 && avg < 80)
grade = 'C';
else if(avg >= 60 && avg < 70)
grade = 'D';
else
grade = 'F';
cout<<"Letter Grade: ";
return grade;
}//endstudentAvg
//calcDeviation
void deviation(int scores[][columns],double devi[][columns], int rows, double avg)
{
for(int i=0; i<rows; i++)
{
for(int j=0; j<columns; j++)
{
devi[i][j] = scores[i][j] - avg;
}
}
}//endDeviation
//calcVariance
void variance(double devi[][columns], int rows)
{
double v = 0;
for(int i=0; i<rows; i++)
{
for(int j=0; j<columns; j++)
{
v += pow(devi[i][j], 2);
}
}
v= v/rows;
cout<<"Variance: "<<v<<endl;
}//endVariance
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