rungeKutta-oridinarydifferentialequation.c

#include<stdio.h>

float dydx(float x,float y)
{
	return ((x-y)/2);
}

float rungeKutta(float x0,float y0,float x,float h)
{
	int n = (int)((x-x0)/h);

	float k1,k2,k3,k4,k5;

	float y = y0;

	for(int i =1;i<n;i++)
	{
		k1 = h*dydx(x0,y);
		k2 = h*dydx(x0 + 0.5*h,y + 0.5 * k1);
		k3 = h*dydx(x0 + 0.5*h,y + 0.5 * k2);
		k4 = h*dydx(x0 + h,y + k3);

		y = y + (1.0/6.0)*(k1 + 2*k2 + 2*k3 + k4);

		x0 = x0 +h;
	}

	return y;
}

int main()
{
	float x0 = 0,y = 1,x = 2,h = 0.2;
	
	printf("\nThe value of y at x is :%f",rungeKutta(x0,y,x,h));

	return 0;
}