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pp:2024:scala:l02 [2024/03/08 18:37]
robert.stoica2205 created 		pp:2024:scala:l02 [2025/03/05 10:47] (current)
pdmatei
Line 18: Line 18:
 <code scala> <code scala>
 def doubler(): Int => Int = { def doubler(): Int => Int = {
 +   ???
 +}
 +</​code>​
 +
 +**2.1.3** Create a function ''​trycatch''​ that takes an integer and evaluates its value using the try function. If an error occurs (try function returns 0), the catch function will be called instead.
 +<code scala>
 +def trycatch(t: Int => Int, c: Int => Int)(x: Int): Int = {
 +   ???
 +}
 +</​code>​
 +
 +**2.1.4** Write a function ''​realtrycatch''​ where t and c take no parameters and produce a result upon evaluation. If an error occurs (try function returns 0), the catch function will be called instead.
 +<code scala>
 +def realtrycatch(t : => Int, c: => Int): Int = {
    ???    ???
 } }
Line 23: Line 37:
  
 ===== 2.2 Custom high order functions ===== ===== 2.2 Custom high order functions =====
 +
 **2.2.1** Define the function ''​foldWith''​ which uses an operation ''​op''​ to reduce a range of integers to a value. For instance, given that ''​op''​ is addition (+), the result of folding the range 1 to 3 will be 1+2+3=6. ''​foldWith''​ should be curried (it will take the operation and return another function which expects the bounds). **2.2.1** Define the function ''​foldWith''​ which uses an operation ''​op''​ to reduce a range of integers to a value. For instance, given that ''​op''​ is addition (+), the result of folding the range 1 to 3 will be 1+2+3=6. ''​foldWith''​ should be curried (it will take the operation and return another function which expects the bounds).
 <code scala> <code scala>
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 </​code>​ </​code>​
  
-**2.2.2** Define the function ''​foldConditional''​ which extends ''​foldWith''​ by also adding a predicate ''​p:​ Int => Int''​. ''​foldConditional''​ will reduce only those elements of a range which satisfy the predicate.+**2.2.2** Define the function ''​foldConditional''​ which extends ''​foldWith''​ by also adding a predicate ''​p:​ Int => Boolean''​. ''​foldConditional''​ will reduce only those elements of a range which satisfy the predicate.
  
 <code scala> <code scala>
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 def compare(x: Int, y: Int, z: Int): Int = def compare(x: Int, y: Int, z: Int): Int =
 { {
-  if x > y && x > z then  +  if (x > y && x > z) x 
-    ​x +  else if (y > x && y > z) y 
-  else if y > x && y > z then +  else z
-    ​y +
-  else +
-    ​z+
 } }
 </​code>​ </​code>​