statistics.cpp

00001 
00002 #include "statistics.h"
00003 #include "mbed.h"
00004 
00005     /**************************************************************************
00006      * This function initializes the private members of the class Statistics  *
00007      **************************************************************************/
00008     statistics::statistics(int* Input, int dataLengthIn, int firstDataPointIn){
00009         data = Input;
00010         dataLength = dataLengthIn;
00011         firstDataPoint = firstDataPointIn;
00012         }
00013         
00014     /**************************************************************************
00015      * This function returns the mean(average) of an array.                   *
00016      **************************************************************************/
00017     double statistics::mean(){
00018         double sum;
00019         for(int i = firstDataPoint; i < (firstDataPoint + dataLength); ++i)
00020         {
00021             sum += data[i];
00022         }
00023     
00024         double average = sum/dataLength;
00025         return average;
00026     }
00027     
00028     /**************************************************************************
00029      * This function returns the standard deviation of an array. This is      *
00030      * used to determine whether the data is valid or not.                    *
00031      **************************************************************************/
00032     double statistics::stdev(){
00033         double sum = 0.0, mean, standardDeviation = 0.0;
00034         printf("The length of the array is %d\n", dataLength);
00035         //double num = (pow(2.0,2.0));
00036         //printf("2^2 is %f\n", num);
00037         //int i;
00038 
00039         for(int i = firstDataPoint; i < (firstDataPoint + dataLength); ++i)
00040         {
00041             sum += data[i];
00042             printf("%d\n", data[i]);
00043         }
00044     
00045         mean = sum/dataLength;
00046     
00047         for(int i = firstDataPoint; i < (firstDataPoint + dataLength); ++i) {
00048             //standardDeviation += pow(data[i] - mean, 2);
00049             standardDeviation += (data[i] - mean)*(data[i] - mean);
00050             }
00051     
00052         return sqrt(standardDeviation / dataLength);
00053     }