Introduction to C++ — Revision Notes

Definition

Syntax

#include <iostream>
using namespace std;

int main() {
    // your code here
    return 0;
}

Example

#include <iostream>
using namespace std;

int main() {
    cout << "Hello, World!" << endl;
    return 0;
}

Output

Important Points

• C++ adds object-oriented features (classes, objects) on top of C.
• cout and cin come from the iostream header for output and input.
• using namespace std; lets you write cout instead of std::cout.
• C++ has a huge standard library called the STL (Standard Template Library).

Common Mistakes

• Forgetting to #include <iostream> before using cout.
• Mixing up << (used with cout) and >> (used with cin).
• Omitting using namespace std; and then forgetting the std:: prefix.

Interview Tip