error handling

exercises/error_handling/errors2.rs

@@ -16,18 +16,21 @@
 // There are at least two ways to implement this that are both correct-- but
 // one is a lot shorter! Execute `rustlings hint errors2` for hints to both ways.
 
-// I AM NOT DONE
-
 use std::num::ParseIntError;
 
 pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
     let processing_fee = 1;
     let cost_per_item = 5;
     let qty = item_quantity.parse::<i32>();
+    match qty {
+        Ok(qty) => Ok(qty * cost_per_item + processing_fee),
+        Err(e) => Err(e),
+    }
 
-    Ok(qty * cost_per_item + processing_fee)
+    //Ok(qty * cost_per_item + processing_fee)
 }
 
+
 #[cfg(test)]
 mod tests {
     use super::*;

exercises/error_handling/errors3.rs

@@ -4,11 +4,9 @@
 // Why not? What should we do to fix it?
 // Execute `rustlings hint errors3` for hints!
 
-// I AM NOT DONE
-
 use std::num::ParseIntError;
 
-fn main() {
+fn main() -> Result<(), ParseIntError>{
     let mut tokens = 100;
     let pretend_user_input = "8";
 
@@ -20,6 +18,7 @@ fn main() {
         tokens -= cost;
         println!("You now have {} tokens.", tokens);
     }
+    Ok(())
 }
 
 pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {

exercises/error_handling/errors4.rs

@@ -1,8 +1,6 @@
 // errors4.rs
 // Make this test pass! Execute `rustlings hint errors4` for hints :)
 
-// I AM NOT DONE
-
 #[derive(PartialEq, Debug)]
 struct PositiveNonzeroInteger(u64);
 
@@ -14,7 +12,13 @@ enum CreationError {
 
 impl PositiveNonzeroInteger {
     fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
+        if value > 0{
             Ok(PositiveNonzeroInteger(value as u64))
+        }else if value < 0{
+            Err(CreationError::Negative)
+        }else{
+            Err(CreationError::Zero)
+        }
     }
 }