public class StdIn
    boolean isEmpty()
    int readInt()
    double readDouble()
    long readLong()
    boolean readBoolean()
    char readChar()
    String readString()
    String readLine()
    String readAll()

public class StdDraw
// The default scale is the unit square (all coordinates between 0 and 1).
    void line(double x0, double y0, double x1, double y1)
    void point(double x, double y)
    void text(double x, double y, String s)
    void circle(double x, double y, double r)
    void filledCircle(double x, double y, double r)
    void square(double x, double y, double r)
    void filledSquare(double x, double y, double r)
    void polygon(double[] x, double[] y)
    void filledPolygon(double[] x, double[] y)
    void setXscale(double x0, double x1)
    void setYscale(double y0, double y1)
    void setPenRadius(double r)  // default pen radius is .002
    void setPenColor(Color c)
    void setFont(Font f)
    void setCanvasSize(int w, int h)
    void clear()
    void clear(Color c)
    void show(int dt)
    void show()
    void save(String filename)

public class StdAudio
    void play(String file)
    void play(double[] a)
    void play(double x)
    void save(String file, double[] a)
    double[] read(String file)