Added Display trait for hash256::Solution

hw7/task1/src/hash256.rs

 use hasher_sha256::{Hasher, HashResult};
 use hasher_sha256::Sha256;
+use std::fmt;
 
 /// Dieser Datentyp beschreibt die Lösung des Hashverfahrens.
 pub struct Solution {
     pub hash: String,
 }
 
+/// Display-Implementierung für den Datentyp Solution
+impl fmt::Display for Solution {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "Number: {} --> hash: {}", self.number, self.hash)
+    }
+}
+
 /// `verify_product` dient der Verifikation eines gefundenen Hashes.
 pub fn verify_product(base: usize, number: usize, difficulty: &String) -> Option<Solution> {
     let sol = base * number;