Programming Fundamentals Using C++

First-Program Exercise

Week 0 · ~30–45 min · the final proof of your setup · ← Orientation hub

This is the last setup step and the first real exercise. You will type, compile, run — and then deliberately break — your first program. Do it with the Getting Started lesson open in another tab if you want the “why” behind each line.

Save it as cpp-course/unit-00/hello.cpp (or any folder — this is a one-file day). Type it; don’t paste it. The typos you are about to make and fix are the lesson — and they go in your bug diary.

The program

// hello.cpp — my first C++ program
// Compile: g++ -std=c++17 -Wall -Wextra hello.cpp -o hello
// Run:     ./hello            (Windows: .\hello.exe)

#include <iostream>

int main() {
    std::cout << "Hello, world!\n";
    return 0;
}

Step 1 — Compile and run

Windows (PowerShell):

g++ -std=c++17 -Wall -Wextra hello.cpp -o hello
.\hello.exe

Linux:

g++ -std=c++17 -Wall -Wextra hello.cpp -o hello
./hello

macOS:

clang++ -std=c++17 -Wall -Wextra hello.cpp -o hello
./hello

Expected:

Hello, world!

A clean compile prints nothing first — silence is success — and then your run prints the line. If the compiler complained: compare your file character-by-character with the listing above; every difference is a discovery. Write each one in your bug diary.

Step 2 — Predict, then check

For each change: write your prediction first, then edit, save, recompile, run, compare. (Remember the loop: every change needs a fresh compile — the old executable doesn’t update itself.)

  1. Change the message to "Hello, C++!\n".
  2. Add a second output line before return: std::cout << "I am programming.\n";
  3. Delete the \n from the first message. What exactly changes?
  4. Change \n to \t in the first message. What appears between the words?

Step 3 — Break it on purpose (three classic errors)

Make each change one at a time, compile, read the error, write down what the compiler said, fix it, recompile:

  1. Remove the ; at the end of the std::cout line.
  2. Misspell std::cout as std::cuot.
  3. Remove the closing } of main.

Each one produces a different compiler complaint — these three messages will follow you for weeks, and you have now met them on your terms.

Step 4 — Make it yours

Personalise the program so it prints a three-line introduction:

Hello, I am Ayesha.
I am learning C++.
Wish me luck!

Requirements: three output lines, at least one chained << (std::cout << "Hello, I am " << "Ayesha.\n";), zero warnings.

Done means

[ ] Compiles warning-free on my machine
[ ] Runs and prints my three lines
[ ] Predictions from Step 2 written down and checked
[ ] Three deliberate breaks from Step 3 made, read, and fixed
[ ] At least one bug diary entry

All five? Setup is complete — go to the Setup Checklist and tick section 7, then start Unit 01 · Lesson 1 where this same program is dissected line by line.

Stuck on any step? Troubleshooting has the named fix for every common failure.

← Orientation hub · Exercises · Lab 00