automation with for loop and while statements in R - r

Question

Most of the times there are more than one ways to implement a solution for a specific problem. Hence, there are bad solutions and good solutions. I consider robust implementations the ones that include for loops and while statements, lists or any other function and build-in types that makes our life easier.
I am looking forward to see and understand some examples of high-programming in R.
Assume a task like the following.
#IMPORT DATASET
Dataset <- read.table("blablabla\\dataset.txt", header=T, dec=".")
#TRAINING OF MODEL
Modeltrain <- lm(temperature~latitude+sea.distance+altitude, data=Dataset)
#COEFFICIENT VALUES FOR INDEPENDENT VARIABLES
Intercept <- summary(Modeltrain)$coefficients[1]
Latitude <- summary(Modeltrain)$coefficients[2]
Sea.distance <- summary(Modeltrain)$coefficients[3]
Altitude <- summary(Modeltrain)$coefficients[4]
#ASK FOR USER INPUT AND CALCULATE y
i <- 1
while (i == 1){
#LATITUDE (Xlat)
cat("Input latitude value please: ")
Xlat <- readLines(con="stdin", 1)
Xlat <- as.numeric(Xlat)
cat(Xlat, "is the latitude value. \n")
#LONGTITUDE (Xlong)
#CALCULATE DISTANCE FROM SEA (Xdifs)
cat("Input longtitude value please: ")
Xlong <- readLines(con="stdin", 1)
Xlong <- as.numeric(Xlong)
#cat(Xlong, "\n")
Xdifs <- min(4-Xlong, Xlat)
cat(Xdifs, "is the calculated distance from sea value. \n")
#ALTITUDE(Xlat)
cat("Input altitude value please: ")
Xalt <- readLines(con="stdin", 1)
Xalt <- as.numeric(Xalt)
cat(Xalt, "is the altitude value. \n")
y = Intercept + Latitude*Xlat + Sea.distance*Xdifs + Altitude*Xalt
cat(y, "is the predicted temperature value.\n")
}
First of all, i would like to ask how to, instead of blablabla\\dataset.txt, set an absolute path making the script functional in other OS too.
Second question is how do i automate the above process, to include additional X variables as well, without having to add them manually in the script.
I understand the latest question probably means re-writing the whole thing therefore i don't expect an answer. As i said before i am more interested in understanding how it could be done and do it myself.
Thanks.
p.s. please don't ask for a reproducible example i can't provide much else.

Answer 1

For the first question, you may want to look at the file.path command. For the second, I would approach this by defining, outside the while loop, two lists, one to store the prompts (e.g. list(lat="Please enter Latitude")) and another, with identical names, to store the input values. Then another loop inside the while iterates through the names of the first list, produces the relevant prompt, and stores the response in the named slot in the second list.
If your users are happy interacting with R in such a way, then you're lucky. Else, as #Roland suggests, delegate the UI to some other technology.