Question

break语句让你提前从for或while语句中离开。在嵌套循环里，break只从最里面的循环离开。

这是上节例子的改进。为何用break是好主意呢？

a = 0; fa = -Inf;
b = 3; fb = Inf;
while b-a > eps*b
   x = (a+b)/2;
   fx = x^3-2*x-5;
   if fx == 0
      break
   elseif sign(fx) == sign(fa)
      a = x; fa = fx;
   else
      b = x; fb = fx;
   end
end
x