Question

NO POINTERS TO BE USED. This is C programming.
I am trying to make a function to calculate standard deviation from a hard coded array. Why is my function not returning my stddev value back to main? I keep getting an error saying that stddev is undeclared.

#include <stdio.h>
#include <math.h>

float calcstddev(float examgrades[], int size)
{
   float sum =0.0;
   float mean;
   int temp;
   float variance;
   float stddev;
   float difference;
   for (temp=0;temp<size;++temp)
   {
       sum+=examgrades[temp];
   }
   mean = sum/size;
   for (temp=0;temp<size;++temp)
   {
   stddev+=pow(examgrades[temp]-mean,2);
   }
   stddev/=size;
   stddev=sqrt(stddev);
   return stddev;
}

int main()
{
  
   float examgrades[]={90,95,90,82,80,87,92};
   calcstddev(examgrades,7);
   printf("The standard deviation is %.4f", stddev);
}

Answer 1

Without pointer there is only one method get value by a function(Not main) which is to collect data returned by function in a varaible.

Code with small modication is given:

#include <stdio.h>
#include <math.h>


float calcstddev(float examgrades[], int size)
{
   float sum =0.0;
   float mean;
   int temp;
   float variance;
   float stddev;
   float difference;
   for (temp=0;temp<size;++temp)
   {
       sum+=examgrades[temp];
   }
   mean = sum/size;
   for (temp=0;temp<size;++temp)
   {
   stddev+=pow(examgrades[temp]-mean,2);
   }
   stddev/=size;
   stddev=sqrt(stddev);
   return stddev;
}

int main()
{
  
   float examgrades[]={90,95,90,82,80,87,92};
   float stddev=calcstddev(examgrades,7);
   printf("The standard deviation is %.4f", stddev);
}

If you didn't mean that in question please comment.