►Programming Language Design (Fall 2009)
▼2 Assignments
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sum-coins
area-cylinder
area-pipe1
area-pipe2
tax
netpay
what-kind
time
time-diff
position
circ
square
rect
area
translate-shape
in-shape?
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2.3 Basic Scheme

You must complete this assignment by yourself.

You must submit this in an archive named "basic.zip".

You must submit this in a file named "basic.ss".

Develop the following functions and datatypes in the Beginning Student language.

(sum-coins pennies nickels dimes quarters) → number?
  pennies : number?
  nickels : number?
  dimes : number?
  quarters : number?
The local supermarket needs a program that can compute the value of a bag of coins. sum-coins produces the amount of money in the bag.

(area-cylinder base-radius height) → number?
  base-radius : number?
  height : number?
Returns the surface area of a cylinder.

You will want to use check-within to test this.

(area-pipe1 inner-radius    
  length    
  wall-thickness) → number?
  inner-radius : number?
  length : number?
  wall-thickness : number?
Computes the surface area of a pipe, which is an open cylinder.

You will want to use check-within to test this.

(area-pipe2 inner-radius    
  length    
  wall-thickness) → number?
  inner-radius : number?
  length : number?
  wall-thickness : number?
Write a version of area-pipe1 that uses several helper functions.

You will want to use check-within to test this.

(tax gross-pay) → number?
  gross-pay : number?
Produces the amount of tax owed. For a gross pay of $240 or less, the tax is 0%; for over $240 and $480 or less, the tax rate is 15%; and for any pay over $480, the tax rate is 28%.

(netpay hours-worked) → number?
  hours-worked : number?
Determines the net pay of an employee, which is the gross pay minus the tax. Assume the hourly pay rate is $12.

(what-kind a b c) → symbol?
  a : number?
  b : number?
  c : number?
The function consumes the coefficients a, b, and c of a quadratic equation. It then determines whether the equation is degenerate and, if not, how many solutions the equation has. The function produces one of four symbols: 'degenerate, 'two, 'one, or 'none. An equation is degenerate if (= a 0).

(struct time (hours minutes seconds))
  hours : number?
  minutes : number?
  seconds : number?
Represents points in time since midnight. Define using define-struct.

(time-diff t1 t2) → number?
  t1 : time?
  t2 : time?
Returns the number of seconds from t1 to t2.

(struct position (x y))
  x : number?
  y : number?
Represents two dimensional points.

(struct circ (center radius))
  center : position?
  radius : number?
Represents circles.

(struct square (upper-left length))
  upper-left : position?
  length : number?
Represents squares.

(struct rect (upper-left width height))
  upper-left : position?
  width : number?
  height : number?
Represents rectangles.

(area shape) → number?
  shape : (or/c circ? square? rect?)
Computes the area of the shape.

You will want to use check-within to test this.

(translate-shape shape delta) → (or/c circ? square? rect?)
  shape : (or/c circ? square? rect?)
  delta : number?
Produces a shape whose key position is moved by delta pixels in the x direction.

(in-shape? shape p) → boolean?
  shape : (or/c circ? square? rect?)
  p : position?
Returns true if p is within the shape, false otherwise.

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