Assignment2.Rmd

---
title: "Assignment 2"
author: "Aadi Kalloo"
date: "November 3, 2015"
output: html_document
---

The following code computes choose(n,r):

```{r}
calc_choose <- function(n,r)
{ 
  # declare all local variables
  n1 <- n;
  r1 <- r;
  n_factorial <- 1;
  nr_factorial <- 1;
  r_factorial <- 1;
  nchooser <- 1;
  nr <- n - r;
  
  #set up three repeat loops. one each for n!, (n-r)!, and r!
  repeat  
  {
      if (n1==0) {break}

      n_factorial = n_factorial*n1;
      n1 = n1 - 1;
  }
    
  repeat  
  {
    if (nr==0) {break}
      
    nr_factorial = nr_factorial*nr;
    nr = nr - 1;
  }
    
  repeat  
  {
    if (r1==0) {break}
      
    r_factorial = r_factorial*r1;
    r1 = r1 - 1;
  }
  
  #compute n choose r
  nchooser = n_factorial/(nr_factorial*r_factorial)
  
  #return answer
  return(nchooser)  
  
}

#This function allows user to enter integer and passes to variable
readinteger <- function()
{ 
  n <- readline(prompt="Enter an integer: ")
  return(as.integer(n))
}

```


The following code tests the above function:

```{r}
n <- readinteger();   #Enter value for n
r <- readinteger();   #Enter value for r
nchooser = calc_choose(n,r);
nchooser

```