Math not computing correctly

[Shaddow]

My problem is that my summation function is not working correctly.

when I subtract the Integer value minus the mean I do not get the correct answer.

I am trying to get (x-mean)^2

The answer I get on the calculator is -6.5 while my program computes -6.25.
The other values in the function are all a bit off as well

I'm sure I am making some dumb mistake.

Thanks in advance for the help!

//Includes ***************************************************

#include<iostream> // for cin and cout
#include<cmath>    // for square root function sqrt()
using namespace std; // for cin and cout in <iostream>


//Constants **************************************************
float Val1 = 16;							    //Given Integer Value 1
float Val2 = 21;							//Given Integer Value 2
float Val3 = 23;							//Given Integer Value 3
float Val4 = 29;							//Given Integer Value 4
double IntValMean = (Val1 + Val2 + Val3 +Val4)/4; //Compute Mean Value of the Integers
double RunTotal = 0.0;					// Running Total for Summations
double Deviation = 0.0;                   // Calculated Standard Deviation
//Functions***************************************************

double Summation()
{
  //Calculate the Summation for each individual integer
	RunTotal = (Val1-IntValMean)*(Val1-IntValMean);
	RunTotal = RunTotal + ((Val2-IntValMean)*(Val2-IntValMean));
	cout << ((Val1-IntValMean)*(Val1-IntValMean)) << endl;
	cout << ((Val2-IntValMean)*(Val2-IntValMean)) << endl;
	cout << ((Val3-IntValMean)*(Val3-IntValMean)) << endl;
	cout << ((Val4-IntValMean)*(Val4-IntValMean)) << endl;
	RunTotal = RunTotal + ((Val3-IntValMean)*(Val3-IntValMean));
	RunTotal = RunTotal + ((Val4-IntValMean)*(Val4-IntValMean));
	return RunTotal;
}

[Shaddow]

oh and I have tried declaring the values like Val1 with a decimal like 16.0 and it does not make a difference

I have also tried switching to all doubles and to all floats with no difference

[Danny Toledo]

Is this the entire code?

[Shaddow]

no....do you want all of it?

[rocketboy9000]

yes, otherwise we can't figure it out as well.

[Shaddow]

//Includes ***************************************************

#include<iostream> // for cin and cout
#include<cmath> // for square root function sqrt()
using namespace std; // for cin and cout in <iostream>


//Constants **************************************************
float Val1 = 16; //Given Integer Value 1
float Val2 = 21; //Given Integer Value 2
float Val3 = 23; //Given Integer Value 3
float Val4 = 29; //Given Integer Value 4
double IntValMean = (Val1 + Val2 + Val3 +Val4)/4; //Compute Mean Value of the Integers
double RunTotal = 0.0; // Running Total for Summations
double Deviation = 0.0; // Calculated Standard Deviation
//Functions***************************************************

double Summation()
{
//Calculate the Summation for each individual integer
RunTotal = (Val1-IntValMean)*(Val1-IntValMean);
RunTotal = RunTotal + ((Val2-IntValMean)*(Val2-IntValMean));
cout << ((Val1-IntValMean)*(Val1-IntValMean)) << endl;
cout << ((Val2-IntValMean)*(Val2-IntValMean)) << endl;
cout << ((Val3-IntValMean)*(Val3-IntValMean)) << endl;
cout << ((Val4-IntValMean)*(Val4-IntValMean)) << endl;
RunTotal = RunTotal + ((Val3-IntValMean)*(Val3-IntValMean));
RunTotal = RunTotal + ((Val4-IntValMean)*(Val4-IntValMean));
return RunTotal;
}
double StdDeviation()
{
double PreSqrd = RunTotal/(4-1); //Summation/(n-1) as part of formula
double EvalDev = sqrt(PreSqrd); //Take the Square Root to finish std dev equation
Deviation = EvalDev;
return Deviation; //Evaluated Standard Devitation Equation

}

void ResulPrint(double Dev, double Mean) {
cout << "The Standard Deviation of the Integers " << Val1 << "," << Val2 << ",";
cout << Val3 << ", and " << Val4 << " is:" << endl << endl;
cout << Dev << endl <<endl;
cout << "and their mean value is:" << endl <<endl;
cout << IntValMean << endl;
}

// Main Function**********************************************
int main() {
// Call the Standard Deviation Function
Summation();
StdDeviation();

//Print Result + Mean Value to Screen
ResulPrint(Deviation,IntValMean);

//Program Wait for Termination
char exit_char; // Temporary for input
cout << "\nPress any key and <enter> to exit \n";
cin >> exit_char; //Wait for key response before exiting.
return 0;
}

[/code]

[rocketboy9000]

Which of these is wrong? I don't get it, what -6.25?

39.0625
1.5625
0.5625
45.5625
The Standard Deviation of the Integers 16,21,23, and 29 is:

5.37742

and their mean value is:

22.25

Press any key and <enter> to exit