external func
a=0.
b=1.
abserr=0.0000
relerr=0.0000001
call  quanc8(func,a,b,abserr,relerr,result,errest,nofun,flag)
print *,result*4.,errest
stop
end
function func(x)
func=sqrt(abs(1.-x*x))
return
end