// Program to test the e-mail claim:
// "If the population of China walked past you, 8 abreast, the line would never
// end because of the rate of reproduction.
// China's birth rate for 2007, taken from:
// http://www.indexmundi.com/china/birth_rate.html
birthrate = 13.45 / 1000 / year
//println[(1/birthrate) -> years]
// China population estimate, June 2007
// http://wikitravel.org/en/China
pop = 1_321_851_888
// Number of people marching abreast
numAbreast = 8
// Marching speed. This is taken from an estimate of my walking speed. (About
// 3.4 mph, reduced for marching.)
speed = 2 mph
// Distance between rows.
distance = 5 feet
// Distance marched per year
distPerYear = year * speed
// Linear density of people
density = numAbreast / distance
// Number of people that march by per unit time
personvelocity = density * speed
println[personvelocity + " people walk by in a second."]
println[(personvelocity * year -> "million") + " people walk by in a year."]
timestep = 1 week
time = 0 s
remaining = pop
do
{
println[format[time, years, 2] + "\t" + format[pop,1,0] + "\t" + format[remaining,1,0]]
time = time + timestep
remaining = remaining - (personvelocity * timestep)
// Change "pop" to "remaining" in the equation below if only people who
// *haven't* marched by yet are eligible to add new kids to the line.
born = pop * birthrate * timestep
pop = pop + born
remaining = remaining + born
} while remaining > 0