> Example problems:
 
> 1. Write a loop to draw N circles in a horizontal row, each of diameter 50, 
> and starting at x=0, y=100. The y coordinate never changes; 
> the x coordinate is incremented by 50 each time.
 
	x=0; y=100;
	for (i=0; i<N; i++) {
	    g.drawOval(x,y,50,50);	// x,y isn't the center, but...
	    x += 50;			// so circles touch
	}
 
> 2. Write a loop to add up the numbers from 1 to N. 
> Put it inside a function that takes N as a parameter.

	public int sumnums(int N) {
	    int i; 
	    int sum = 0;
	    for (i=1; i<=N; i++) {
	        sum += i;
	    }
	    return sum;
	}

> 3. Write a function printMultiple that takes two parameters, 
> an int n and a char ch, and prints n copies of that character: 
> printMultiple('a', 4) should yield aaaa. 
 
	public void printMultiple(int n, char ch) {
	    int i;
	    for (i=0; i<n; i++) System.out.print(ch);
	}

> 4. *Using* the function printMultiple above, write a loop to draw
>         *
>         ***
>         *****
>         *******
> (each row has two more *'s than the previous row.)
 
    int starcount = 1;
    for (row=1; row<= maxrow; row++) {		// suppose maxrow is given
        printMultiple(starcount, '*');
        starcount += 2;			// increase by 2 each time
    }

> 5. Write a function that reverses a string:
>         public String reverse (String s) {
>         }
> This one is hard, although we did do a class example about this.
> Hint: let n = s.length(). The letters of s are s.charAt(n-1) down to 
> s.charAt(0). Append these (with +=) in turn to an initially empty string.

	public String reverse (String s) {
	    int n;
	    String rev = "";
	    for (n=s.length()-1; n>=0; n--) {	// note s.length() - 1
	        rev += s.charAt(n);
	    }
	    return rev;
	}