Heavy Metal Tribe

#include
#include
void main()
{
  float pi,e1,e2,m,x0,x1,x2,tfc,pm0,pm1,pm2,w,t,d,pm;
  float k1,k2,k3,k4,l1,l2,l3,l4,deld,delw,dg;
  FILE *fp1,*fp2;
  fp1=fopen("input.dat","r");
  fp2=fopen("output.txt","w");
  fscanf(fp1,"%f%f%f%f%f%f%f%f",&pi,&e1,&e2,&m,&x0,&x1,&x2,&tfc);
  pm0=(e1*e2)/x0;
  pm1=(e1*e2)/x1;
  pm2=(e1*e2)/x2;
  w=0;
  d=asin(pi/pm0);
  for(t=0;t<=1;t=t+.05)
  {
   dg=d*180/3.1414;
   fprintf(fp2,"\n%f%f",t,dg);
   if(t=tfc)
   pm=pm2;
   k1=w*.05;
   l1=(pi-pm*sin(d))*.05/m;
   k2=(w+.5*l1)*.05;
   l2=(pi-pm*sin(d+.5*k1))*.05/m;
   k3=(w+.5*l2)*.05;
   l3=(pi-pm*sin(d+.5*k2))*.05/m;
   k4=(w+l3)*.05;
   l4=(pi-pm*sin(d+k3))*.05/m;
   deld=(k1+2*k2+2*k3+k4)/6;
   delw=(l1+2*l2+2*l3+l4)/6;
   d=d+deld;
   w=w+delw;
   }
   }

Input data for swing curve:
Pi = 0.9
e1=1.1
e2=1.0
M=0.016