Introduction

Engineers often work with logical operations. Logic is critical to dynamic control. An excellent example of this exists in transportation engineering. Conditional logic operations are needed to manage the complex track schedules for light$-$rail transit $($LRT$)$ systems.

The following demonstrates input$/$outputcontrol for an LRT system. The operational logic of an LRT junction is to be implemented for user$-$defined input with a C$++$ program.

Program Specification

Consider an LRT junction with four input tracks and one output track. The output track can handle only one train at a time. Therefore, the LRT junction will only clear one train for travel from amongst all the trains on all the input tracks. The one train cleared for travel is selected by a ranking of track priorities as follows:

$-$ The input track with the highest number of trains on it is given the highest priority and will have one train cleared for travel. All other trains on that highestpriority track and the other tracks are stopped.

$-$ If equal numbers of trains exist on any input tracks, the following order of priority, from highest to lowest, is used: Track $4,$ Track $3,$ Track $2,$ Track $1.$

$-$ If the highest priority track $($with the cleared train$)$ has four or more stopped trains, an alert is generated for that track.