Write a program to solve first and second order ordinary differential equations (initial value problem) using Runge-Kutta fourth order method.

#include<stdio.h>
#include<conio.h>
#include<math.h>
#include<stdlib.h>
float fun(float x,float y)
{
 return(x+fabs(sqrt(y)));
}
void main()
{
 float y,x,h,e,k1,k2,k3,k4,k;
 int n,i;
 clrscr();
 printf("\n enter the value of x0:");
 scanf("%f",&x);
 printf("\n enter the value of y0:");
 scanf("%f",&y);
 printf("\n enter step length h: ");
 scanf("%f",&h);
 printf("\n enter the vlaue of x at which y is needed :");
 scanf("%f",&e);
 n=(e-x)/h;
 for(i=1;i<=n;i++)
 {
  printf("%d the iteration \n",i);
  k1=h*fun(x,y);
  k2=h*fun(x+h/2,y+k1/2);
  k3=h*fun(x+h/2,y+k2/2);
  k4=h*fun(x+h,y+k3);
  k=(k1+2*k2+2*k3+k4)/6;
  y=y+k;
  x=x+h;
  printf("\n the value of y at x=%f is %f",x,y);
  }
  getch();
  }