Newton’s Forward and Backward interpolation
Source Code:
#include< stdio.h>
#include< math.h>
int main()
{
float x[10],y[15][15];
int n,i,j;
printf("Enter n : ");
scanf("%d",&n);
printf("X\tY\n");
for(i = 0;i< n;i++){
scanf("%f %f",&x[i],&y[i][0]);
}
//forward difference table
for( j=1;j< n;j++)
for(i=0;i< ( n-j);i++)
y[i][j] = y[i+1][j-1] - y[i][j-1];
printf("\n***********Forward Difference Table ***********\n");
//display Forward Difference Table
for(i=0;i< n;i++)
{
printf("\t%.2f",x[i]);
for(j=0;j< (n-i);j++)
printf("\t%.2f",y[i][j]);
printf("\n");
}
//backward difference table
for(j=1;j(j-1);i--)
y[i][j] = y[i][j-1] - y[i-1][j-1];
printf("\n***********Backward Difference Table ***********\n");
//display Backward Difference Table
for(i=0;i< n;i++)
{
printf("\t%.2f",x[i]);
for(j=0;j< =i;j++)
printf("\t%.2f",y[i][j]);
printf("\n");
}
return 0;
}