new file:   l3p2c.py
	new file:   l3p5a.py
	new file:   l3p5b.py
	new file:   l3p5c.py
	new file:   l3p9.py
	new file:   l4p10.py
	new file:   l4p11.py
	new file:   l4p3.py
	new file:   l4p4.py
	new file:   l4p5.py
	new file:   l4p8.py
	new file:   l4p9.py
	new file:   l5p1.py
	new file:   l5p2.py
iterative greatest common divisor
recursive greatest common divisor
iterative length of string
recursive length of string
bisection search character into the string
bisection search character into the string