Can Ruby call methods or procs like c calls functions? - c

Question

I am pretty new to Ruby. I am college and just did a programming course that covered regular c. My final project for class was a slop intercept project, which was fairly easy, but i had to use functions for everything, for example:
#include <stdio.h>
#include <math.h>
int get_problem(int *choice){
do {
printf("Select the form that you would like to convert to slope-intercept form: \n");
printf("1) Two-Point form (you know two points on the line)\n");
printf("2) Point-slope form (you know the line's slope and one point)\n");
scanf("%d", &*choice);
if (*choice < 1 || *choice > 2){
printf("Incorrect choice\n");}
}while (*choice != 1 && *choice !=2);
return(*choice);
}
...
int main(void);
{
char cont;
do {
int choice;
double x1, x2, y1, y2;
double slope, intercept;
get_problem (&choice);
...
I have several more functions completing the entire program. I got a new job and i need to start learning Ruby, So for my first project I wanted to convert this program into Ruby, now I was able simply get rid of the functions and just run it without methods or procs. I wanted to know if it is possible to do the same thing, define a method, then call the method without giving an input, but getting back the variables stored in the method. Would it be possible using methods or procs. Here is a little of what i have so far using a proc.
get_problem = Proc.new {
begin
puts "Select the form that you would like to convert to slope-intercept form: "
puts "1) Two-Point form (you know two points on the line)"
puts "2) Point-slope form (you know the lines slope and one point)"
choice = gets.chomp.to_i
if (choice < 1 || choice > 2)
puts "Incorrect choice"
end
end while (choice != 1 && choice !=2)
}
....
begin
get_problem.call
case choice
when 1
get2_pt.call
display2_pt.call
slope_intcpt_from2_pt.call
when 2
get_pt_slope.call
display_pt_slope.call
intcpt_from_pt_slope.call
Now I know I probably have it all wrong, but I figured I would give it a shot. I have it as methods before where I had
def get_problem(choice)
....
end
....
get_problem(choice)
....
Is there something basic I am missing? As you can see, i used pointers in c and had to initialize the variables in the main.
Thank you for taking the time to help me out.
Robert

Answer 1

You can't pass a pointer to a variable in Ruby, but I don't think you need to do that to accomplish what you're trying to do. Try this:
def get_problem
puts "Select the form that you would like to convert to slope-intercept form: "
puts "1) Two-Point form (you know two points on the line)"
puts "2) Point-slope form (you know the lines slope and one point)"
loop do
choice = gets.chomp.to_i
return choice if [1, 2].include? choice
STDERR.puts "Incorrect choice: choose either 1 or 2"
end
end
choice = get_problem
puts "The user chose #{choice}"
This defines a method get_problem which loops until the user chooses either 1 or 2, and returns their chosen number, which you can store in a top-level variable choice.