xq自動交易

請問一下大神，如果我想寫出布林寬帶，"連續3天"都在某個百分比內的話，我要如何改寫下列的語法呢，因為下面的寫法只會是只有當期的寬帶計算，謝謝大神解惑

input:leng1(20,"計算天期");

input:width(1.5,"帶寬%");

variable:up1(0),down1(0),mid1(0),bbandwidth(0);

up1 = bollingerband(Close[1], 20, 2);

down1 = bollingerband(Close[1], Leng1, -2 );

mid1 = (up1 + down1) / 2;

bbandwidth = 100 * (up1 - down1) / mid1;

if bbandwidth <width then ret=1;