在算法框图中高考的热点是循环结构,常以填空形式考查输出结果,我们首先要认准初值,循环体,循环条件(或终止条件),采用步步逐推法,数列求和公式法,递推数列求项法,就能够快速准确解题,请看以下三例.一、步步逐推法例1(2009年海南).如 The heat of the entrance examination in the algorithm block diagram is a cyclic structure, often fill in the blank form to examine the output, we must first look for the initial value, loop body, cycle conditions (or termination conditions), step by step by law, , Recursive sequence to find the item method, you can quickly and accurately solve the problem, see the following three cases. First step by step by law 1 (Hainan 2009).