Computing Standard Deviation In C++

Exercise:

Write a C++ program that uses arrays to calculate standard deviation of 5 data entries.

Click Here to View the Solution:
#include <iostream> 
#include <cmath>
using namespace std;
float SD(float Data[]);
int main()
{
    float Data[5];    //number of entries can be changed
    cout << "Insert 5 Data entries:\n";
    for(int x = 0; x < 5; ++x)
    {
        cout << x+1 << ". ";
        cin >> Data[x];
    }
    cout << endl << "Standard Deviation is: " << SD(Data);
    return 0;
}
float SD(float Data[])
{
    float sum = 0.0, mean, ans = 0.0;
    for(int x = 0; x < 5; ++x)
    {
        sum += Data[x];
    }
    mean = sum/10;
    for(int x = 0; x < 5; ++x)
    ans += pow(Data[x] - mean, 2);
    return sqrt(ans / 5);
}
Click Here to View the Output:
 Insert 5 Data entries:
 23
 3.5
 13.63
 9.2
 10 
 Standard Deviation is: 8.75968
Click Here to View the Explanation:
  • This code creates a user-defined function SD(). 5 entries are requested to be entered by the user.
  • After the user enters 5 elements, they are stored as an array.
  • This function SD () is then called in the main () function. Standard deviation for the entered numbers is calculated by the function.
  • The answer is printed on the screen.
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