Simple data plugging

Measurements.c

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

#define Ra 4.7 //The constant resistance
#define Ein 10 //Input voltage
#define Rx 1 //True value
int size; //Number of readings you're going to input

void resistance(double *volt, double *resi);
void mean(double *Rb, double *mean);
void meanDeviation(double *mean, double *resi, double *deviation);
void avgDeviation(double *deviation, double *avgDev);
void stdDeviation(double *deviation, double *stdDeviation);
void rangeFu(double *resi, double *range);
void impresFu(double *resi, double *impres);


int main()
{
    printf("Enter the number of readings:");
    scanf("%d",&size);
    
    double Eo[size],Rb[size],meanVr,devMean[size],avgDev,stdDevRes,range,impres[size]; //If you see squiggly lines here, ignore them
    double *Eptr;
    Eptr = Eo;


    for(int i=0; i<size; i++)
    {
        printf("Enter reading number %d: ",(i+1));
        scanf("%lf",(Eptr+i));
        if(*(Eptr+i) >= Ein) //Eliminating negative resistance values
        {
            printf("The value of reading you entered was more than %d.\n",Ein);
            return 1;
        }
        else if (*(Eptr+i) <= 0) //Eliminating runtime errors errors
        {
            printf("The value of the reading your entered was zero or negative.\n");
            return 1;
        }
    }
    /*Data plugging*/
    resistance(&Eo[0],&Rb[0]);
    mean(&Rb[0],&meanVr);
    meanDeviation(&meanVr,&Rb[0],&devMean[0]);
    avgDeviation(&devMean[0], &avgDev);
    stdDeviation(&devMean[0], &stdDevRes);
    rangeFu(&Rb[0],&range);
    impresFu(&Rb[0],&impres[0]);
    /* Printing output starts*/
    for(int j=0; j<size; j++)
    {
        printf("The value of resistance number %d = %lf\n", (j+1), Rb[j]);
    }
    for(int k=0; k<size; k++)
    {
        printf("Deviation from mean for resistance number %d = %lf\n",(k+1),*(devMean+k));
    }
    for(int l=0; l<size; l++)
    {
        printf("Error for resistance number %d = %lf\n",(l+1),impres[l]);
    }
    printf("The average deviation = %lf\n",avgDev);
    printf("Standard deviation = %lf\n",stdDevRes);
    printf("Mean = %lf\n",meanVr);
    printf("Range = %lf\n",range);
    /*printing output ends*/
}

void resistance(double *volt, double *resi)
{//calculating the value of the resistance and plugging it into an array
    for(int j=0; j<size; j++)
    {
        *(resi+j) = (Ra * (*(volt+j)))/(Ein-(*(volt+j)));
    }
}

void mean(double *Rb, double *mean)
{
    double numerator = 0;
    for(int k=0; k<size; k++)
    {
        numerator += *(Rb+k);
    }
    *mean = numerator/size;
}

void meanDeviation(double *mean, double *resi, double *deviation)
{
    for(int l=0; l<size; l++)
    {
        *(deviation+l) = (*(resi+l) - *(mean));
    }
}

void avgDeviation(double *deviation, double *avgDev)
{
    for(int m=0; m<size; m++)
    {
        *(deviation+m) = sqrt(*(deviation+m) * *(deviation+m)); //Modulus
    }
    double sigmaDev = 0;
    for(int n=0; n<size; n++)
    {
        sigmaDev += *(deviation+n);
    }
    *avgDev = (sigmaDev)/size;
}

void stdDeviation(double *deviation, double *stdDeviation)
{
    double devSqr[size];
    for(int i=0; i<size;i++)
    {
        devSqr[i] = (*(deviation+i)) * (*(deviation+i)); //squaring
    }
    double sigmadevSqr;
    for(int j=0; j<size; j++)
    {
        sigmadevSqr += devSqr[j];
    }

    *stdDeviation = sqrt(sigmadevSqr/(size-1));
}

void rangeFu(double *resi, double *range)
{
    double Rmax=0,Rmin=500;
    for(int i=0; i<(size); i++)
    {   //Selecting the highest value
        if(*(resi+i) > Rmax)
        {
            Rmax = *(resi+i);
        }
        //Selecting the lowest value
        if(*(resi+i) < Rmin)
        {
            Rmin = *(resi+i);
        }
    }
    *range = sqrt((Rmax - Rmin) * (Rmax - Rmin));
}

void impresFu(double *resi, double *impres)
{
    for(int i=0; i<size; i++)
    {
        *(impres+i) = (sqrt((*(resi+i) - Rx) * (*(resi+i) - Rx))/Rx) * 100; //Modulus
    }
}