Furthering a CPlusPlus Exercise

[dune]

I found these exercises through a search: https://www.cplusplus.com/forum/articles/12974/

I'm down to the Bracketing Search exercise and have coded the bot to answer in 10 or less tries, but I can't get the bot to guess in 7 tries or less each time, as is part of the exercise.

#include <iostream>
#include <cstdlib>
#include <ctime>

using std::cout, std::cin;
using std::rand, std::srand;

int main() {
    int min {1};
    int max {100};
    int botGuess {0};

    int secretNumber{54}; // hard-coded number for the bot to guess
    int guesses{0};
    int range{0};

    cout << "I'm thinking of a number between 1 and 100.\n";
    srand(time(nullptr));

    do {
        cout<< "Your guess: ";
        range = (max - min) + 1;
        botGuess = rand() % range + min;
        cout<< botGuess;
        ++guesses;

        if (botGuess > secretNumber) {
            cout << "\nToo high!\n";
            max = botGuess - 1;
        } else if (botGuess < secretNumber) {
            cout << "\nToo low!\n";
            min = botGuess + 1;
        }
    } while (botGuess != secretNumber);

    cout<< "\nWell done, bot!\n";
    cout << "Took you " << guesses << " tries to guess " << botGuess << '\n';


    return 0;
}

So what can I do to make the bot guess in 7 tries or less?

btw: thank to cire for the excellent explanation of rand(), found here https://www.cplusplus.com/forum/beginner/85134/

[jonnin]

guessing games are just a twist on the binary search.
100 is max.
pick 50. 1*
its higher or lower, 54 is higher, pick 150/2 = 75 *2
75 is too high, (50+75)/2 is 62. too high. *3
50+62 / 2 is 56 *4, too high. 50+56/ 2 is 53 *5, too low. 53+56... 54 got it. *6 guesses.

its ensures to win in 7 tries, 2^7 is 128 which > 100. But its boring, it will guess the same first few values (eg 50, 25 or 75, ..) every time: its not a guessing game at that point, its an optimal solution.

[dune]

@jonnin - Thank you for showing me what I asked for. I found this to be a nice challenge. So it served its purpose, in that regard. And cire's post made rand() more clear. Thanks for your explanation. Easy to see what you're talking abt.

[dutch]

cire's post made rand() more clear.

Perhaps you should read it again.
range should be set to max - min + 1, not just max.
Think about what would happen if min wasn't 1.

[dune]

Got it covered in Line 22. But I did change Line 15

int range = max; // busy busy busy and not paying attention.

to

int range{0};

Since I was only initializing range with max, it all worked out. Sure didn't look right, though. Thanks for spotting that.