1. Write a function called c_to_f in R that converts from 
celsius to farenheit

2. Rewrite the following function in R so that it runs
faster (and is written more compactly):

length_normalize <- function(v){
	# normalize all the values in v by the sum of the
	# values in the vector
	sum <- 0
	
	for( i in v){
		sum <- sum + i
	}
	
	for(i in 1:length(v)){
		v[i] <- v[i] / sum
	}
	
	return(v)
}