Permisi gan ane mau tanya nih, ane lagi buat program buat hitung regresi pakai bahasa C, nah semua berjalan benar sampai pada hasil dari sigma X itu hasilnya 0, ane udah cek logikanya udah betul kira-kira adakah yang terlewat

Source Code ane :
<code>
#include <stdio.h>
#include <stdlib.h>

int i,n,j,k,l;
int dataX[],dataY[];
double hasilXY[],hasilX2[],hasilY2[],hasilYa[],hasilEr[],sX,sY,sXY,sX2,sY2,s2X,a,b;
int main()
{
printf("Program Untuk Forecast dengan Teknik Regresi\n\n");
printf("Masukan Banyak data forecast :");
scanf("%d",&n);
for (i=0;i<n;i++) {
printf("\nMasukan Nilai X%d : ",i+1);
scanf("%d",&dataX[i]);
printf("\nMasukan Nilai Y%d : ",i+1);
scanf("%d",&dataY[i]);
}
printf("\n================================================\n");
proses();
getch();
}
void proses() {
printf("Banyak data : %d\n",n);
i =0;
for (i=0;i<n;i++) {
printf("Nilai X%d : %d\n",i+1,dataX[i]);
printf("Nilai Y%d : %d\n",i+1,dataY[i]);
} j=0;
for (j=0;j<n;j++) {
hasilXY[j] = dataX[j]*dataY[j];
hasilX2[j] = dataX[j]*dataX[j];
hasilY2[j] = dataY[j]*dataY[j];
printf("\nNilai XY%d : %lf",j+1,hasilXY[j]);
printf("\nNilai X2(%d) : %lf",j+1,hasilX2[j]);
printf("\nNilai Y2(%d) : %lf",j+1,hasilY2[j]);
}
printf("\n===============================================\n");
Mulai dari sini ada yang ganjil gan
k=0;sX=0.0;sY=0.0;sXY=0.0;sX2=0.0;
for (k=0;k<n;k++) {
sX = sX+dataX[k];
sY = sY+dataY[k];
sXY = sXY+hasilXY[k];
sX2 = sX2+hasilX2[k];
}
printf("\nSigma X : %lf",sX);
printf("\nSigma Y : %lf",sY);
printf("\nSigma XY : %lf",sXY);
printf("\nSigma X2 : %lf", sX2);
printf("\n===============================================\n");
b = (n*sXY-sX*sY)/(n*sX2-(sX*sX));
a = (sY-b*sX)/n;
printf("\n================================================\n");
printf("\n Nilai a : %lf",a);
printf("\n Nilai b : %lf",b);
printf("\n===============================================\n");
l=0;
for (l=0;l<n;l++) {
hasilYa[l] = a + b*dataX[l];
hasilEr[l] = abs(hasilYa[l]-dataY[l]);
printf("Nilai Y%d aksen : %lf",l+1,hasilYa[l]);
printf("\nNilai Error%d : %lf",l+1,hasilEr[l]);
}
printf("\n==================== END =======================\n");
}

</code>