Implement the cubic spline using c programming.

Code:

#include

#include

#include

int main()

{

    char choice='y';

    int n,i,j,k;

    float h[10],a,b,c,d,sum,s[10]={0},x[10],F[10],f[10],p,m[10][10]={0},temp;

    clrscr();

    cout<<"No of samples ? ";cin>>n;

    cout<<"enter all sample points: "<

    for(i=0;i

    cin>>x[i]>>f[i];

    for(i=n-1;i>0;i--)

    {

        F[i]=(f[i]-f[i-1])/(x[i]-x[i-1]);

        h[i-1]=x[i]-x[i-1];

    }

for(i=1;i

    {

    m[i][i]=2*(h[i-1]+h[i]);

    if(i!=1)

    {

        m[i][i-1]=h[i-1];

        m[i-1][i]=h[i-1];

    }

    m[i][n-1]=6*(F[i+1]-F[i]);

    }

for(i=1;i

    {

        temp=(m[i+1][i]/m[i][i]);

        for(j=1;j<=n-1;j++)

            m[i+1][j]-=temp*m[i][j];

    }

for(i=n-2;i>0;i--)

    {

        sum=0;

        for(j=i;j<=n-2;j++)

            sum+=m[i][j]*s[j];

        s[i]=(m[i][n-1]-sum)/m[i][i];

    }

    while(choice=='y')

    {

        cout<>p;

        for(i=0;i

            if(x[i]<=p&&p<=x[i+1])

            {

            a=(s[i+1]-s[i])/(6*h[i]);

            b=s[i]/2;

            c=(f[i+1]-f[i])/h[i]-(2*h[i]*s[i]+s[i+1]*h[i])/6;

            d=f[i];

            sum=a*pow((p-x[i]),3)+b*pow((p-x[i]),2)+c*(p-x[i])+d;

            }

        cout<<"coefficients of sub interval : "<

        cout<

        cout<<"wanna continue (y/n) ? ";cin>>choice;

    }

    getch();

    return 0;

}