Question

I coded an easy game. I know how to use cout/cin but having problems with printf/scanf. The code below works well with cout/cin. Question is, how to convert them into printf/scanf? Why the codes in comment don’t work?

Edit: I mean if I delete cout/cin lines and when I use printf/scanf instead it doesn’t work properly.

#include <iostream>
#include <time.h>

using namespace std;

int main()
{
    srand(time(NULL));
    int min=0, max=1000, guess, counter=0;
    bool winner=false;
    char answer;

    while(counter<10){
        guess = rand()%(max-min)+min;
        // printf("Did you pick %d? \t", guess);
        // scanf("%c", &answer);
        cout << "Did you pick " << guess << "?\t";
        cin >> answer;
        if(answer=='y'){ // yes
            winner=true;
            // printf("Computer wins.\n");
            // printf("You picked: %d", guess);
            cout << "Computer wins." << endl;
            cout << "You picked: " << guess;
            break;
        }
        else if(answer=='m'){ // more
            min=guess;
            counter++;
        }
        else if(answer=='l'){ // less
            max=guess;
            counter++;
        }
    }
    if(winner==false){
        // printf("User wins.\n");
        cout << "User wins." << endl;
    }
    return 0;
}

Answer 1

The problem is that scanf() doesn’t remove the newline ‘\n’ character from stdin, so on the next iteration the next scanf() reads it and tries to process it, seeming to ignore the input.
Try this instead:

scanf("\n%c", &answer);

That way, you expect the newline and scanf() consumes it.