C++ I/O, Variables and References

C++

#include <iostream>
#include <string>
using namespace std;

int main() {
    string name;
    int age;
    cout << "Enter name and age: ";
    cin >> name >> age;
    cout << "Hello " << name << ", you are " << age << endl;

    auto pi = 3.14159;      // type deduced as double
    bool ok = true;
    cout << boolalpha << ok << " " << pi << endl;
    return 0;
}

Enter name and age: Asha 20 Hello Asha, you are 20 true 3.14159

References

A reference is an alias for an existing variable. It must be initialised and can't be re-seated.

C++

#include <iostream>
using namespace std;

void doubleIt(int &n) { n *= 2; }   // pass by reference

int main() {
    int x = 10;
    int &r = x;
    r = 25;
    doubleIt(x);
    cout << x << endl;
    return 0;
}

Pointer vs ReferenceA pointer can be null and can be re-pointed; a reference can't be null and always refers to the same object.

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