File : distance.bush

Calculate the distance between two points on the Earth's surface.

#!/usr/local/bin/bush

--- Calculate the distance between two points on the Earth's surface

pragma annotate( "Distance" );
pragma annotate( "" );
pragma annotate( "Calculate the distance between two points on the Earth's surface" );
pragma annotate( "by Ken O. Burtch" );
pragma ada_95;
pragma restriction( no_external_commands );

procedure distance is

  here_lat   : float;
  here_long  : float;
  there_lat  : float;
  there_long : float;
  distance_raw : float;

  earth_radius : constant float := 3963.0;

begin

  put( " Starting Latitude: " );
  here_lat := numerics.value( get_line );
  put( "Starting Longitude: " );
  here_long := numerics.value( get_line );

  put( "   Ending Latitude: " );
  there_lat := numerics.value( get_line );
  put( "  Ending Longitude: " );
  there_long := numerics.value( get_line );

  new_line;

  distance_raw :=
    numerics.sin( here_lat, 360 ) * numerics.sin( there_lat, 360 ) +
    numerics.cos( here_lat, 360 ) * numerics.cos( there_lat, 360 ) *
    numerics.cos( there_long - here_long, 360 );

  distance := earth_radius * numerics.arccos( distance_raw );

  put_line( "Distance between the two places is" );
  put( distance, "ZZZZZ.99999" );
  put_line( " miles" );

end distance;

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