WEEK 1

# 1.
# Generic function to calculate the factorial of any input integer.
calc.factorial = function(inp){
  inpFact = inp
  for (ctr in (inp-1):1){
    inpFact <- inpFact * ctr
  }
  print(sprintf("%1.0f Factorial is %1.0f",inp,inpFact))
  return(inpFact)
}

# 1. Alternate
# Specific function to calculate the factorial of the number 12.
calc.12factorial = function(){
  inpFact = 12
  for (ctr in 11:1){
    inpFact <- inpFact * ctr
  }
  print(sprintf("12 Factorial is %1.0f",inpFact))
  return(inpFact)
}

# 2.
# A function to create a numeric vector that contains an arithmetic sequence of N terms, 
# given the first & last terms, and the common difference.
arithSequence = function(term1, termN, comDiff){

  #Find the total number of terms in the sequence
  termCount <- (termN - term1)/comDiff + 1
  
  #Create a vector to store the sequence in
  mySequence <- 1:termCount
  
  print("The Arithmetic Sequence is: ") 
  
  #Calculate, store, and print the terms of the sequence one by one, while looping though the vector
  for(i in 1:termCount){
    mySequence[i] <- term1+((i-1)*comDiff)
    print(sprintf("%d",mySequence[i])) 
  }
}

# 3.
# A function to solve any quadratic equation specified by the 3 co-efficient terms as inputs to the function
quadratic = function(a,b,c){
  sol1 = 0
  sol2 = 0
  
  sol1 = (0 - b + sqrt(b^2 - (4 * a * c)))/(2 * a)
  sol2 = (0 - b - sqrt(b^2 - (4 * a * c)))/(2 * a)
  
  print(sprintf("Solution to this quadratic equation: x = %1.2f, and x = %1.2f", sol1, sol2))
}



# Call the generic function to calculate the factorial of any number, with input 12.
calc.factorial(12)

## [1] "12 Factorial is 479001600"

## [1] 479001600

# Call the specific function to calculate the fcatorial of 12.
calc.12factorial()

## [1] "12 Factorial is 479001600"

## [1] 479001600

# Call the function to solve a quadratic equation.
quadratic(6,-17,12)

## [1] "Solution to this quadratic equation: x = 1.50, and x = 1.33"

# Call the function to store an arithmetic sequence in a vector and print it.
arithSequence(20,50,5)

## [1] "The Arithmetic Sequence is: "
## [1] "20"
## [1] "25"
## [1] "30"
## [1] "35"
## [1] "40"
## [1] "45"
## [1] "50"