#include<stdio.h>
#include<math.h>
#include<conio.h>
main ()
{
double i,x0,xn,h,yold,ynew,error,k1,k2,k3,k4;
double yRunge(double y),yture(double x);
clrscr();
x0=0.0;
xn=1.0;
h=0.01;
yold=1.0;
for(i=x0;i<=xn;i+=h){
k1=h*yRunge(yold);
k2=h*yRunge(yold+k1/2.0);
k3=h*yRunge(yold+k2/2.0);
k4=h*yRunge(yold+k3);
ynew=yold+k1/6.0+k2/3.0+k3/3.0+k4/6.0;
yold=ynew;
error=yold-yture(i);
printf("i=%lf yold=%lf error=%lf\n",i,yold,error);
}

getch();
}
double yRunge(double y)
{
return y;
}
double yture(double x)
{
return exp(x);
}