Write a c programme to perform Lagrange's interpolation formula?

Answer 1

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

main() { float

x[10],y[10],temp=1,f[10],sum,p; int

i,n,j,k=0,c; clrscr(); printf("\nhow many record you will be enter: "

); scanf("%d"

,&n); for

(i=0; i<n; i++) { printf("\n\nenter the value of x%d: "

,i); scanf("%f"

,&x[i]); printf("\n\nenter the value of f(x%d): "

,i); scanf("%f"

,&y[i]); } printf("\n\nEnter X for finding f(x): "

); scanf("%f"

,&p); for

(i=0;i<n;i++) { temp = 1; k = i; for

(j=0;j<n;j++) { if

(k==j) { continue

; } else

{ temp = temp * ((p-x[j])/(x[k]-x[j])); } } f[i]=y[i]*temp; } for

(i=0;i<n;i++) { sum = sum + f[i]; } printf("\n\n f(%.1f) = %f "

,p,sum); getch(); }