import java.util.Scanner; import java.util.Random; import java.text.DecimalFormat; class GolfPracticeRange3 { public static void main( String[] args ) { // // welcome message & golfing ability question... // System.out.println( "===================================\n" + "Welcome to the Golf Practice Range!\n" + "===================================\n" ); System.out.println( "What is your golfing ability?" ); System.out.println( "\n-----------------------------------\n" + " EXAMPLE PLAYER TYPES...\n" + "-----------------+-----------------\n" + " who | golfing ability\n" + "-----------------+-----------------\n" + " Little Sally | 0.55\n" + " Luc Devroy | 0.6\n" + " Grampa Golfer | 0.7\n" + " Frequent Golfer | 0.75\n" + " \"The Rock\" | 0.8\n" + " Average Pro | 0.95\n" + " Tiger Woods | 1.0\n" ); System.out.print( "\nPlease enter a number, between 0.1 and 1.0,\n" + "corresponding to your \"golfing ability\" ==> " ); Scanner scan = new Scanner( System.in ); double golfing_ability = scan.nextDouble(); scan.skip("\n"); // work-around for nextDouble bug in Scanner class // // check the golfing ability and if it's out of range, set a default // if ( (golfing_ability < 0) || (golfing_ability > 1.0) ) { System.out.println( "\nSorry, I don't understand; I'll chose for you..." ); golfing_ability = 0.5; System.out.println( "\n\nYou'll be hitting with ability: " + golfing_ability + " that of Tiger Woods." ); } // // generate a random number for the magnitude of the vertical offset // Random generator = new Random(); double vertical_offset = generator.nextFloat(); // // generate a random number for the sign of the vertical offset; // if vertical_offset is zero, we want it to look like "0", not "-0" // int up_or_down = generator.nextInt(2); // 0 (down) or 1 (up) if ( up_or_down == 0 && vertical_offset != 0 ) { up_or_down = -1; } // // combine the vertical offset factors (sign and magnitude) // vertical_offset = up_or_down * vertical_offset; // meters // // range length will is: max 330 yards // generate a random number for the... // magnitude of the horizontal offset (distance to target) // final double meters_per_yard = 0.9144; int yards_to_target = 30 + generator.nextInt(301); // 30 to 330 int meters_to_target = (int) (yards_to_target * meters_per_yard); // // club-face angles (loft) // final double w1a = 13.0; // 14.0 degrees; real club loft: 10.0 final double w3a = 15.0; // 19.5 degrees; real club loft: 15.0 final double i3a = 16.5; // 24.0 degrees; real club loft: 21.0 final double i4a = 17.5; // 26.0 degrees; real club loft: 24.0 final double i5a = 19.0; // 28.0 degrees; real club loft: 27.0 final double i6a = 20.5; // 31.0 degrees; real club loft: 31.0 final double i7a = 22.5; // 35.0 degrees; real club loft: 35.0 final double i8a = 25.0; // 42.0 degrees; real club loft: 39.0 final double i9a = 28.0; // 45.0 degrees; real club loft: 43.0 // // club maximum yardages // (as expected by Tiger Woods) // final double w1my = 300; // yards final double w3my = 265; // yards final double i3my = 240; // yards final double i4my = 227; // yards final double i5my = 213; // yards final double i6my = 200; // yards final double i7my = 187; // yards final double i8my = 173; // yards final double i9my = 160; // yards // // club swing-speed coefficients // (maximum yardage as compared with the 1 wood) // final double w1ssc = (double) w1my/w1my; // 1.00 final double w3ssc = (double) w3my/w1my; // 0.88 final double i3ssc = (double) i3my/w1my; // 0.80 final double i4ssc = (double) i4my/w1my; // 0.76 final double i5ssc = (double) i5my/w1my; // 0.71 final double i6ssc = (double) i6my/w1my; // 0.67 final double i7ssc = (double) i7my/w1my; // 0.62 final double i8ssc = (double) i8my/w1my; // 0.58 final double i9ssc = (double) i9my/w1my; // 0.53 // // reveal the target // DecimalFormat Dfmt2 = new DecimalFormat( "0.##" ); String target = "target is " + meters_to_target + " meters (" + yards_to_target + " yards) away,\n" + "and " + Dfmt2.format(vertical_offset) + " meters " + "in height, relative to your position."; System.out.println( "\n\nThe " + target ); // // club selection question... if it's out of range, set a default // System.out.println( "\n-----------------------\n" + " YOUR CLUBS...\n" + "--------+-------+------\n" + " club | angle | code\n" + "--------+-------+------\n" + " 1 wood | " + w1a + " | 1w\n" + " 3 wood | " + w3a + " | 3w\n" + "--------+-------+------\n" + " 3 iron | " + i3a + " | 3i\n" + " 4 iron | " + i4a + " | 4i\n" + " 5 iron | " + i5a + " | 5i\n" + " 6 iron | " + i6a + " | 6i\n" + " 7 iron | " + i7a + " | 7i\n" + " 8 iron | " + i8a + " | 8i\n" + " 9 iron | " + i9a + " | 9i\n" ); System.out.print( "\nPlease enter the code of the club you want to use ==> " ); String club_code = scan.nextLine(); // // given the club selection, prepare the club... // String club_name = ""; double club_angle = 0.0; double club_swing_speed_coefficient = 1.0; if ( club_code.equals( "1w" ) ) { club_name = "1 wood"; club_angle = w1a; club_swing_speed_coefficient = w1ssc; } else if ( club_code.equals( "3w" ) ) { club_name = "3 wood"; club_angle = w3a; club_swing_speed_coefficient = w3ssc; } else if ( club_code.equals( "3i" ) ) { club_name = "3 iron"; club_angle = i3a; club_swing_speed_coefficient = i3ssc; } else if ( club_code.equals( "4i" ) ) { club_name = "4 iron"; club_angle = i4a; club_swing_speed_coefficient = i4ssc; } else if ( club_code.equals( "5i" ) ) { club_name = "5 iron"; club_angle = i5a; club_swing_speed_coefficient = i5ssc; } else if ( club_code.equals( "6i" ) ) { club_name = "6 iron"; club_angle = i6a; club_swing_speed_coefficient = i6ssc; } else if ( club_code.equals( "7i" ) ) { club_name = "7 iron"; club_angle = i7a; club_swing_speed_coefficient = i7ssc; } else if ( club_code.equals( "8i" ) ) { club_name = "8 iron"; club_angle = i8a; club_swing_speed_coefficient = i8ssc; } else if ( club_code.equals( "9i" ) ) { club_name = "9 iron"; club_angle = i9a; club_swing_speed_coefficient = i9ssc; } else { System.out.println( "\nSorry, I don't understand; I'll chose for you..." ); // maybe here generate two random numbers... // one for wood or iron, and one for club number club_name = "5 iron"; club_angle = i5a; club_swing_speed_coefficient = i5ssc; } // // remind the user what club they've selected, and its properties // System.out.println( "\n\nYou'll be hitting with a " + club_name + ", which will hit\nyour ball at an angle of " + club_angle + " degrees above the ground." ); // // swing strength question... // System.out.println( "\n---------------------\n" + " SWING STRENGTHS...\n" + "---------------+-----\n" + " Gentle swing | 0.1\n" + " Half strength | 0.5\n" + " Let it rip!!! | 1.0\n" ); System.out.println( "\nHow hard do you want to swing the " + club_name + "?\n" ); System.out.println( "Remember that the " + target ); System.out.print( "\nPlease enter a number, between 0.1 and 1.0,\n" + "corresponding to how you want to swing the club ==> " ); double swing_strength = scan.nextDouble(); scan.skip("\n"); // work-around for nextDouble bug in Scanner class // // check the swing strength input and if it's out of range, set a default // if ( (swing_strength < 0) || (swing_strength > 1.0) ) { System.out.println( "\nSorry, I don't understand; I'll chose for you..." ); swing_strength = 0.5; } // // calculate the initial speed of the ball // // conversion: 0.277777 m/s in 1 km/hr // 33.00 m/s == 120 km/hr (Average Golfer) // 58.06 m/s == 209 km/hr (Tiger Woods, with 1 wood) double max_club_speed_by_super_pro = 58.06; double ball_elacticity_coefficient = 1.35; double initial_speed = max_club_speed_by_super_pro * club_swing_speed_coefficient * Math.sqrt( golfing_ability ) * Math.sqrt( swing_strength ) * ball_elacticity_coefficient; // // tell the user how fast their club choice and swing strength will // launch the ball // DecimalFormat Dfmt1 = new DecimalFormat( "0.#" ); System.out.println( "\n\nSwinging the " + club_name + " with " + swing_strength + " strength, will launch the ball " + Dfmt1.format(initial_speed) + " m/s." ); // // calculate the initial velocity (speed in the x and y direction) // double club_angle_in_radians = club_angle * Math.PI / 180; double vix = initial_speed * Math.cos( club_angle_in_radians ); double viy = initial_speed * Math.sin( club_angle_in_radians ); // // setup the quadratic equation coefficients // final double acceleration_of_gravity = -9.81; // at the surface of Earth double a = 0.5 * acceleration_of_gravity; double b = viy; double c = -1 * vertical_offset; // // quadratic equation calculation // double discriminant = Math.pow(b, 2) - (4 * a * c); //double time1 = ((-1 * b) + Math.sqrt(discriminant)) / (2 * a); double time2 = ((-1 * b) - Math.sqrt(discriminant)) / (2 * a); // // tell the user the ball's flight time // System.out.println( "Your ball's flight time: " + Dfmt2.format(time2) + " seconds"); // // calculate and report the distance to the landing // double hit_distance = vix * time2; // distance to first touch System.out.println( "Distance to where your ball first hit the ground: " + Dfmt2.format(hit_distance) + " meters (" + Dfmt2.format(hit_distance / meters_per_yard) + " yards)" ); // // calculate and report a random extra bounce in (meters) // int randomBounce = generator.nextInt(6); // at most 5 meters System.out.println( "Your ball bounced an extra: " + randomBounce + " meters!" ); // // calculate the distance away from target // meters_to_target -= hit_distance; meters_to_target -= randomBounce; System.out.println( "Meters left to target: " + Dfmt2.format(meters_to_target) + " meters (" + Dfmt2.format(meters_to_target / meters_per_yard) + " yards)" ); // // if target achieved or overshot, say something... // if ( meters_to_target == 0 ) { System.out.println( "\nAmazing!\n" ); } else if ( meters_to_target < 0 ) { System.out.println( "\nOvershot!\n" ); } } }