Forward Difference Table Generation Using C Programming

While interpolating intermediate value of dependent variable for equi-spaced data of independent variable, at the begining of the table, Newton's Forward Interpolation formula is used. This method relies on Forward Difference Table is used. In this article, we are going to generate forward difference table using c programming language.

Program


#include<stdio.h>
#include<conio.h>

int main()
{
 float x[20], y[20][20];
 int i,j, n;
 clrscr();
 /* Input Section */
 printf("Enter number of data?\n");
 scanf("%d", &n);
 printf("Enter data:\n");
 for(i = 0; i < n ; i++)
 {
  printf("x[%d]=", i);
  scanf("%f", &x[i]);
  printf("y[%d]=", i);
  scanf("%f", &y[i][0]);
 }

 /* Generating Forward Difference Table */
 for(i = 1; i < n; i++)
 {
  for(j = 0; j < n-i; j++)
  {
   y[j][i] = y[j+1][i-1] - y[j][i-1];
  }
 }

 /* Displaying Forward Difference Table */
 printf("\nFORWARD DIFFERENCE TABLE\n\n");
 for(i = 0; i < n; i++)
 {
  printf("%0.2f", x[i]);
  for(j = 0; j < n-i ; j++)
  {
   printf("\t%0.2f", y[i][j]);
  }
  printf("\n");
 }

 getch(); /* Holding Screen */
 return 0;
}

Backward Difference Table C Output

Enter number of data?
5
Enter data:
x[0]=40
y[0]=31
x[1]=50
y[1]=73
x[2]=60
y[2]=124
x[3]=70
y[3]=159
x[4]=80
y[4]=190

FORWARD DIFFERENCE TABLE

40.00   31.00   42.00   9.00    -25.00  37.00
50.00   73.00   51.00   -16.00  12.00
60.00   124.00  35.00   -4.00
70.00   159.00  31.00
80.00   190.00

Recommended Readings

  1. Forward Difference Table Generation Using C Programming
  2. Forward Difference Table Generation Using C++ with Output
  3. Backward Difference Table Generation Using C Programming
  4. Backward Difference Table Generation Using C++ with Output