Question

I'm trying to create a function determines the range of outliers in an array using pass by reference.

I need to write a function that outputs the +3 and -3 standard deviation. I'm having a hard time figuring out what I should identify as my pointers and how to use the pass by reference. This is what I have so far:

#include <stdio.h>

#define ARRAY_SIZE 20

double homeworkArray[ARRAY_SIZE] = { 1.3, 5.7, 2.1, -1.2, 0.5, 4.3, 2.1, 50.2, 3.4, 1.1,

-2.1, 4.1, 6.7, 3.9, 4.1, -0.5, -3.3, 2.1, 5.1, -3.1 };

double CalculateMean(double data[], int size)

{

int i;

double sum = 0.0;

for (i = 0; i < size; i++)

{

sum += data[i];

}

return sum / size;

}

double CalculateStandardDeviation(double data[], int size)

{

double mean = CalculateMean(data, size);

double variance = 0.0;

double diff;

int i;

for (i = 0; i < size; i++)

{

diff = data[i] - mean;

variance += diff * diff;

}

return sqrt(variance / (size));}

}

  

int main(int argc, const char * argv[]) {

double lowerRange=0.0, upperRange=0.0;

  

  

double mean = CalculateMean(homeworkArray, ARRAY_SIZE);

double stddev = CalculateStandardDeviation(homeworkArray, ARRAY_SIZE);

printf("Anything outside of (%.2lf - %.2lf) is an outlier.\n",lowerRange,upperRange);

  

return 0;

}

  

Answer 1

Note: Could you plz go this code and let me know if u need any changes in this.Thank You
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#include <stdio.h>
#include <math.h>
#include <stdlib.h>

#define ARRAY_SIZE 20

double homeworkArray[ARRAY_SIZE] = { 1.3, 5.7, 2.1, -1.2, 0.5, 4.3, 2.1, 50.2, 3.4, 1.1,

-2.1, 4.1, 6.7, 3.9, 4.1, -0.5, -3.3, 2.1, 5.1, -3.1 };

double CalculateMean(double data[], int size)

{

int i;

double sum = 0.0;

for (i = 0; i < size; i++)

{

sum += data[i];

}

return sum / size;

}

double CalculateStandardDeviation(double data[], int size)

{

double mean = CalculateMean(data, size);

double variance = 0.0;

double diff;

int i;

for (i = 0; i < size; i++)

{

diff = data[i] - mean;

variance += diff * diff;

}

return sqrt(variance / (size));

}

  
void findOutliers(double* outliers,int *cnt,double lowerRange,double upperRange);
int main(int argc, const char * argv[]) {

double lowerRange=-3, upperRange=3;

  

  

double mean = CalculateMean(homeworkArray, ARRAY_SIZE);

double stddev = CalculateStandardDeviation(homeworkArray, ARRAY_SIZE);

printf("Anything outside of (%.2lf - %.2lf) is an outlier.\n",lowerRange,upperRange);

/* Creating an float array dynamically
* based on the size entered by the user
*/
double* outliers = (double*)malloc(ARRAY_SIZE * sizeof(double));
  
int cnt=0;
  
int i;
findOutliers(outliers,&cnt,lowerRange,upperRange);
for(i=0;i<cnt;i++)
   {
       printf("%.1lf ",outliers[i]);
   }
   printf("\n");
return 0;

}

void findOutliers(double* outliers,int *cnt,double lowerRange,double upperRange)
{
   int i,n=0;
   for( i=0;i<ARRAY_SIZE;i++)
   {
       if(homeworkArray[i]<lowerRange || homeworkArray[i]>upperRange)
       {
           outliers[n]=homeworkArray[i];
           n++;
       }
      
   }
   *cnt=n;
}

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Output:

____________Thank You