The equilibrium stock price is determined by both the supply and the demand side, corresponding to the freeposition of a spring when all external force is removed.
股票的均衡价格是股票的买卖双方处于均衡态势时共同认可的价格，对应于弹簧在无外力作用时的平衡位置。
3
We can use an array to store a linear collection. Adding new elements to an array is easy since we simply place the new element in the first freeposition at the rear of the array.