so far we have used void functionsnow we will be using funct

so far we have used void functions....now we will be using functions that return values. Using the list of numbers provided,,,,,,find the best fit of a streight line through it (regression analysis): to generate the equation y = mx + b (Functions that return values) Use basic header like <iostream>, <fstream>
please comment all the lines...

the data:
35
44
36
12
45
89
96
87
54

Teachers hint:

functions that return values

/*
some suggestions on doing the assignment

THIS IS NOT THE ONLY WAY BUT ONE SUGGESTING THAT MAY
MAKE IT SIMPLE.  

THERE ARE A SERIES OF POD CAST SHOWING HOW TO DO THIS
ASSIGNMENT ON ITUNES U.....UNDER ENGINEERING FOR MCCC
   
*/

using namespace std;

#include <iostream>
#include <fstream>

float x[50], y[50];
int NumOfDataPoints;
float m, b;

float sumX();
float sumY();
float sumXY();
float sumXsq();

int main()
{
   m = ((NumOfDataPoints*sumXY()) - (sumX()*sumY())) / ((NumOfDataPoints*sumXsq()) - (sumX()*sumX()));
   b = ((sumY() - (m*sumX())) / float(NumOfDataPoints));
   cout<<\"y = \"<<m<<\"x\"<<\"+ \"<<b<<endl;
   system(\"pause\");//so you can see the equation printed on the screen above
   //you will have to write all the code for all the
   //functions that return values and creat a function
   //to read data into the arrays.
   return 0;   
}


float sumX()
{
    float ans;
    
    return ans;   
}
      
float sumY()
{
   float ans;
   
   return ans;   
}
      
float sumXY()
{
   float ans;
   
   return ans;     
}
      
float sumXsq()
{
   float ans;
      
   return ans;
}

Solution

C++ program

#include <iostream>
#include <fstream>
using namespace std;
// global variable declerations
float x[50], y[50];
int NumOfDataPoints;
float m, b;
// function declerations
float sumX();
float sumY();
float sumXY();
float sumXsq();

int main()
{
ifstream datFile;
datFile.open(\"data.txt\"); // input data is in the file data.txt
int count = 0;
while(!datFile.eof())
{
datFile >> y[count]; // reading the data from the file
x[count] = count;// The x data
count ++; // increasing the count
}
NumOfDataPoints = count; // number of data points is the count
// computing m and b using function calls
m = ((NumOfDataPoints*sumXY()) - (sumX()*sumY())) / ((NumOfDataPoints*sumXsq()) - (sumX()*sumX()));
b = ((sumY() - (m*sumX())) / float(NumOfDataPoints));
cout<<\"y = \"<<m<<\"x\"<<\"+ \"<<b<<endl;
//system(\"pause\");//so you can see the equation printed on the screen above
return 0;   
}

float sumX()
{
float ans = 0.0;
for(int i = 0;i<NumOfDataPoints;i++)// sum of all x
ans = ans + x[i];
return ans;   
}
  
float sumY()
{
float ans = 0.0;
for(int i = 0;i<NumOfDataPoints;i++) // sum of all y
ans = ans +y[i];
return ans;   
}
  
float sumXY()
{
float ans = 0.0;
for(int i = 0;i<NumOfDataPoints;i++) // sum of all (xy)
ans = ans +x[i]*y[i];
return ans;   
}
  
float sumXsq()
{
float ans = 0.0;
for(int i = 0;i<NumOfDataPoints;i++) // sum of all x^2
ans = ans +x[i]*x[i];
return ans;
}

data.txt

35
44
36
12
45
89
96
87
54

OUTPUT

y = 6.7x+ 28.5333