Runge-Kutta 4th Order Method in C

In numerical analysis, the Runge–Kutta methods are an important family of implicit and explicit iterative methods, which are used in temporal discretization for the approximation of solutions of ordinary differential equations. These techniques were developed around 1900 by the German mathematicians C. Runge and M. W. Kutta.

Program of Runge-Kutta 4th Order in C

  #include<stdio.h>
  #include<conio.h>
  #include<math.h>
  #define f(x,y) (x*y)

  void main()
  {
    int n,i;
    float x,xf,y,h,s,s1,s2,s3,s4;
    clrscr();
    printf("Enter the First value :- ");
    scanf("%d",&x);
    printf("Enter the Second value :- ");
    scanf("%d",&xf);
    printf("Enter the Lenth y :- ");
    scanf("%d",&y);
    printf("Enter the Width h :- ");
    scanf("%d",&h);
    while(x<xf)
    {
        s1=f(x,y);
        s2=f((x+(h/2)),(y+(h/2)*s1));
        s3=f((x+(h/2)),(y+(h/2)*s2));
        s4=f((x+h),(y+h*s3));
        s=(s1+(2*s2)+(2*s3)+s4)/6;
        y=y+(h*s);
        x=x+h;
    }
    printf("Output = %f",y);
    
    getch();
  }
  

Output