This weeks ICSP assignment was to write a program which draws squares. The task was to draw squares from a set list in an array, but I opted rather to accept a command line argument in my script. To write this I had to delve back into regular expression, which I hate because I don’t understand!

The program source is below. You should execute the program from the command line giving the with and height of the square you wish to draw, for example:

java Squares 4x4

And the code:

import java.lang.String;
import java.util.regex.*;

public class Squares{
        public int dimensions[];

        public Squares(String[] args){
                if(args.length==1){
                        Pattern form=Pattern.compile("^\\S+x\\S+$");
                        Matcher fit=form.matcher(args[0]);
                        if(fit.matches()){
                                try{
                                        String[] dims=args[0].split("x");
                                        int width=Integer.parseInt(dims[0]);
                                        int height=Integer.parseInt(dims[1]);
                                        this.dimensions=new int[] {width,height};
                                }
                                catch(NumberFormatException e){
                                        System.err.println("Argument must be a string, width by height, in the form 6x6");
                                        System.exit(1);
                                }
                        }
                        else{
                                System.out.println("Argument must be a string, width by height, in the form 6x6");
                                System.exit(1);
                        }
                }
                else{
                        System.err.println("Please supply an argument, which must be a string, width by height, in the form 6x6");
                        System.exit(0);
                }
        }

        public String draw(){
                int i;
                int z;
                int width=this.dimensions[0];
                int height=this.dimensions[1];
                String square="";

                for(i=0;i<height ;i++){
                        for(z=0;z<width;z++){
                                if((i==0||i==height-1)&&(z==0||z==width-1))
                                        square+="+";
                                else if(z==0||z==width-1)
                                        square+="|";
                                else if((i==0||i==height-1))
                                        square+="-";
                                else
                                        square+=" ";
                        }
                        square+="\n";
                }

                return square;
        }

        public static void main(String[] args){
                Squares square=new Squares(args);
                String draw=square.draw();
                System.out.println(draw);
        }
}