lasd/teoria/esempi_professore/examples/templates/main.cpp

136 lines
2.4 KiB
C++

#include <iostream>
using namespace std;
template <typename Data>
class A;
template <typename Data>
ostream& operator<< (ostream& outstr, const A<Data>& a);
template <typename Data>
class A {
private:
protected:
uint size = 0;
Data* str = nullptr;
public:
A() = default;
A(uint num) : size(num) {
cout << "A new object is created" << endl;
str = new Data[num]();
}
~A() {
delete[] str;
cout << "The object is destructed" << endl;
}
Data& operator[](const uint idx) {
return str[idx];
}
bool operator==(const A& obj) const noexcept {
if (size == obj.size)
{
for (uint i = 0; i < size; i++)
{
if (str[i] != obj.str[i])
{
return false;
}
}
return true;
}
return false;
}
//template <typename DataX>
//friend ostream& operator<<(ostream&, const A<DataX>&);
friend ostream& operator<< <>(ostream&, const A<Data>&);
};
template <typename Data>
ostream& operator<< (ostream& outstr, const A<Data>& a) {
for (uint i = 0; i < a.size; i++) { cout << i << ": '" << a.str[i] << "' "; }
return outstr;
}
int main() {
A<char> var1(2);
A<char> var2(2);
cout << "var1: " << var1 << endl;
cout << "var2: " << var2 << endl;
cout << "var1 ?= var2: " << (var1 == var2) << endl;
var1[0] = 'x';
cout << "var1: " << var1 << endl;
cout << "var2: " << var2 << endl;
cout << "var1 ?= var2: " << (var1 == var2) << endl;
var2[1] = 'y';
cout << "var1: " << var1 << endl;
cout << "var2: " << var2 << endl;
cout << "var1 ?= var2: " << (var1 == var2) << endl;
var1[1] = 'y';
var2[0] = 'x';
cout << "var1: " << var1 << endl;
cout << "var2: " << var2 << endl;
cout << "var1 ?= var2: " << (var1 == var2) << endl;
cout << endl << endl;
A<int> var3(2);
A<int> var4(2);
cout << "var3: " << var3 << endl;
cout << "var4: " << var4 << endl;
cout << "var3 ?= var4: " << (var3 == var4) << endl;
var3[0] = 10;
cout << "var3: " << var3 << endl;
cout << "var4: " << var4 << endl;
cout << "var3 ?= var4: " << (var3 == var4) << endl;
var4[1] = 5;
cout << "var3: " << var3 << endl;
cout << "var4: " << var4 << endl;
cout << "var3 ?= var4: " << (var3 == var4) << endl;
var3[1] = 5;
var4[0] = 10;
cout << "var3: " << var3 << endl;
cout << "var4: " << var4 << endl;
cout << "var3 ?= var4: " << (var3 == var4) << endl;
return 0;
}