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# WealthScript Techniques | Creating a Stop-And-Reverse (SAR) system

## The problem

Let's imagine that you are trying to create a simple Strategy based on fast/slow moving averages crossing.
On crossunder, it must sell long position and turn short.
On crossover, short must be covered and a new long position established.

## Example code

It's a very basic question frequently asked by WealthScript rookies, and there's only one trick to learn: the very first trade should be processed individually by making a check for Positions.Count equal to zero.

using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using WealthLab;
using WealthLab.Indicators;

namespace WealthLab.Strategies { public class SARStrategy : WealthScript { protected override void Execute() { DataSeries maFast = SMA.Series(Close, 50); DataSeries maSlow = SMA.Series(Close, 200);

PlotSeries(PricePane,maFast,Color.Red,LineStyle.Solid,2); PlotSeries(PricePane,maSlow,Color.Green,LineStyle.Solid,2);

for(int bar = 201; bar < Bars.Count; bar++) { // Detect crossover/crossunder and store state in a variable bool maXo = CrossOver(bar, maFast, maSlow); bool maXu = CrossUnder(bar, maFast, maSlow); // The first trade if (Positions.Count == 0){ if ( maXo ) BuyAtMarket( bar + 1 ); else if( maXu ) ShortAtMarket( bar + 1 ); } // Subsequent trades else { Position p = LastPosition; if ( p.PositionType == PositionType.Long ) { if ( maXu ) { SellAtMarket( bar + 1, p ); ShortAtMarket( bar + 1 ); } } else if ( maXo ) { CoverAtMarket( bar + 1, p ); BuyAtMarket( bar + 1 ); } } } } } }

## Another example

Our previous example featured CrossOvers/CrossUnders and AtMarket orders. Here's how to create a SAR strategy working with AtStop orders breaching 100-bar High and Low prices:

using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using WealthLab;
using WealthLab.Indicators;

namespace WealthLab.Strategies { public class SARStrategy : WealthScript { protected override void Execute() { DataSeries HH = Highest.Series(High, 100); DataSeries LL = Lowest.Series(Low, 100);

PlotSeries(PricePane,HH,Color.Blue,LineStyle.Solid,1); PlotSeries(PricePane,LL,Color.Red,LineStyle.Solid,1);

for(int bar = GetTradingLoopStartBar(100); bar < Bars.Count; bar++) { // The first trade if (Positions.Count == 0){ if ( BuyAtStop( bar + 1, HH[bar] ) == null ) ShortAtStop( bar + 1, LL[bar] ); } // Subsequent trades else { Position p = LastPosition; if ( p.PositionType == PositionType.Long ) { if ( SellAtStop( bar + 1, p, LL[bar] ) ) ShortAtStop( bar + 1, LL[bar] ); } else { if (CoverAtStop( bar + 1, p, HH[bar] ) ) BuyAtStop( bar + 1, HH[bar] ); } } } } } }