Reworked functions to detect overflows.

hw6/task1/src/main.rs

     for x in v {
         match x.parse::<i32>() {
             Ok(val) => {
-                sum += val;
+                match i32::checked_add(sum, val) {
+                    Some(y) => {sum = y;}
+                    None => return Err("Overflow"),
+                }
             }
             Err(_) => return Err("Given String is not a int"),
         }
     for x in v {
         match x.parse::<i32>() {
             Ok(val) => {
-                prod *= val;
+                match i32::checked_mul(prod, val) {
+                    Some(y) => {prod = y;}
+                    None => return Err("Overflow"),
+                }
             }
             Err(_) => return Err("Given String is not a int"),
         }