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diff --git a/teoria/enumeration.cpp b/teoria/enumeration.cpp
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diff --git a/teoria/struct.cpp b/teoria/struct.cpp
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+++ b/teoria/struct.cpp
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+#include <iostream>
+using namespace std;
+void differentStructSize();
+void studentStruct();
+
+int main(){
+  studentStruct();
+  return 0;
+}
+
+void studentStructWithConstructor(){
+  struct StudentNoDefaultConstructor{
+    string nome, cognome, matricola;
+    int annoCorso;
+
+    StudentNoDefaultConstructor(string n, string c, string m, int a){
+      nome = m;
+      cognome = c;
+      matricola = m;
+      annoCorso = a;
+    }
+  };
+  struct StudentNoDefaultConstructor st1{"Alan","Turing","N86000000",1}; //OK
+  //struct StudentNoDefaultConstructor st2; //errore. no default constructor
+
+  /* Qui lascia compilare la dichiarazione di st3 ma non permette di lavorarci
+    su, causa costruttore di default mancante. */
+  struct StudentNoDefaultConstructor st3();
+  //st3.nome = "Planck";
+  //cout<<st3.nome;
+
+  struct StudentOnlyDefaultConstructor{
+    string nome, cognome, matricola;
+    int annoCorso;
+    StudentOnlyDefaultConstructor() = default;
+  };
+
+  struct StudentOnlyDefaultConstructor st4;
+  struct StudentOnlyDefaultConstructor st5();
+  //struct StudentOnlyDefaultConstructor st6{"Alan","Turing","N86000000",1}; errore
+}
+
+void studentStruct(){
+  struct Student{
+    string nome, cognome, matricola;
+    int annoCorso;
+  };
+  struct Student st1{"Alan","Turing","N86000000",1};
+  struct Student st2 = {"Kurt","Godel","N86000001",1};
+  //Student st3("Kurt","Godel","N86000001",1); // errore, richiede esplicitamente un costruttore
+  struct Student st4;
+  struct Student st5();
+  cout<<st1.cognome<<" e "<<st2.cognome<<" studiano alla Federico II"<<endl;
+}
+
+void differentStructSize(){
+  /*
+    A causa della struttura di un elaboratore, due struct con gli stessi elementi
+    potrebbero avere una dimensione diversa.
+    Con g++ 7.5.0 senza opzioni di ottimizzazione S1 pesa 96 byte, mentre S2
+    pesa 64 byte.
+  */
+  struct S1{
+    char c1;
+    int i;
+    char c2;
+  };
+  struct S2{
+    char c1,c2;
+    int i;
+  };
+  cout<<sizeof(S1)<<" "<<sizeof(S2)<<endl; //12 8
+}