program main print *, "Hello JSRUN - from gfrotran" end f(x)=cos(x)-0.5 a=0. b=0. 10 c=(a+b)/2.0 na=sign(1.,f(a)) nb=sign(1.,f(b)) nc=sign(1.,f(c)) write(*,*)c,f(c) if(abs(b-a)/2.it.0.0001)goto 20 if(na.eq.nc)a=c if(nb.eq.nc)b=c goto 10 20 end