Full walkthrough

Step 1: Set up the file and the random engine

Include <iostream> for I/O and <random> for proper random numbers. The starter builds a std::mt19937 engine seeded from std::random_device, then a std::uniform_int_distribution<int> dist(1, 100) — the distribution is what guarantees every number from 1 to 100 is equally likely, which rand() % 100 does not.

std::mt19937 rng(std::random_device{}());
std::uniform_int_distribution<int> dist(1, 100);
int secret = dist(rng);

Step 2: Declare the game state

You need three ints: secret (the target), guess (starts at 0 so it cannot accidentally equal the secret), and attempts (starts at 0). Print the invitation line 'I'm thinking of a number from 1 to 100.' before the loop so the player knows the range — the range is a promise the hints rely on.

Step 3: Write the game loop

The whole game is while (guess != secret). Each iteration prompts 'Your guess: ', reads with std::cin, and increments attempts before comparing. Counting the attempt before the comparison means the winning guess is counted too — players expect 'found in 5 attempts' to include the final guess.

while (guess != secret) {
    std::cout << "Your guess: ";
    if (!(std::cin >> guess)) return 0;
    ++attempts;
    if (guess < secret)      std::cout << "Too low!\n";
    else if (guess > secret) std::cout << "Too high!\n";
}

Step 4: Handle bad input inside the read

The if (!(std::cin >> guess)) return 0; guard means typing 'abc' ends the program politely instead of looping forever on a broken stream. It is one line, and it is the difference between a demo and a program you can hand to someone else.

Step 5: Announce the win with the attempt count

When the loop condition fails, the guess equals the secret, so print 'Correct in N attempts!'. Notice there is no separate win check inside the loop — the loop condition IS the win check. That is the pattern to remember: let the loop condition carry the game's end state.

Step 6: Add the play-again prompt from the checklist

Wrap the whole game in a do/while: after a win, ask 'Play again? (y/n)' and read a char. If it is 'y', draw a fresh secret with dist(rng) and reset attempts to 0 — forgetting to reset either one is the classic bug here, and the game feels broken immediately.

Step 7: Test with a strategy, then with chaos

Play using binary search: guess 50, then halve the range each time — you should always win within 7 attempts for 1–100, which proves the hints are truthful. Then test chaos: guess 0, 101, and letters, and confirm the program behaves sensibly every time.