执行下边的程序框图，输出的n =（）——2022 高考数学第 7 题答案解析

【答案】B【解析】【分析】根据框图循环计算即可.【详解】执行第一次循环， $b = b + 2 a = 1 + 2 = 3$ $a = b - a = 3 - 1 = 2 , n = n + 1 = 2$

$$ \left| \frac {b ^ {2}}{a ^ {2}} - 2 \right| = \left| \frac {3 ^ {2}}{2 ^ {2}} - 2 \right| = \frac {1}{4} > 0. 0 1; $$

执行第二次循环， $b = b + 2 a = 3 + 4 = 7$

$$ a = b - a = 7 - 2 = 5, n = n + 1 = 3, $$

$$ \left| \frac {b ^ {2}}{a ^ {2}} - 2 \right| = \left| \frac {7 ^ {2}}{5 ^ {2}} - 2 \right| = \frac {1}{2 5} > 0. 0 1; $$

执行第三次循环， $b = b + 2 a = 7 + 1 0 = 1 7$

$$ a = b - a = 1 7 - 5 = 1 2, n = n + 1 = 4, $$

$\left| { \frac { b ^ { 2 } } { a ^ { 2 } } } - 2 \right| = \left| { \frac { 1 7 ^ { 2 } } { 1 2 ^ { 2 } } } - 2 \right| = { \frac { 1 } { 1 4 4 } } < 0 . 0 1$ ，此时输出 $n = 4$

故选：B