bug using getch

[gabzz29]

bug at getch it does not let me choose again, i dont want to use a while loop because it has more code

#include <iostream>
#include <conio.h>
using namespace std;

int main (){
    int opt;
    menu:
    cout << "Calculator.\n";
    cout << "1.ADDITION\n";
    cout << "2.SUBTRACTION\n";
    cout << "3.MULTIPLICATION\n";
    cout << "4.DIVISION\n";
    cout << "Select an option:";
    cin >> opt;

    switch(opt){
        case 1:
        double x,y,ans;
        cout << "----ADDITION----\n";
        cout << "Enter two integers:";
        cin >> x >> y;
        
        ans = x + y;
        cout << x << " + " << y << " = " << ans;
        break;

        case 2:
        cout << "----SUBTRACTION----";
        cout << "Enter two integers:";
        cin >> x >> y;

        ans = x - y;
        cout << x << " - " << y << ans;
        break;

        case 3:
        cout << "----MULTIPLICATIOMN";

        default:
        cout << "INVALID INPUT.";
    }
    getch();
    goto menu;
    

}

[AbstractionAnon]

You're sadly mistaken if you think a while (true) loop generates more code than your goto. What do think a while (true) loop generates? Guess what, it generates a label and a goto under the covers. In other words, it's identical to what you've coded.

Now for the lecture: gotos are a very bad habit to get into. They lead to unmaintainable programs. A while loop clearly conveys to the reader that you want the code to continue (loop). A goto does NOT convey that. A goto implies you want to jump somewhere in the program. Not necessarily back to the beginning.

As a beginning programmer, it's good that you're concerned about the size of your program, but to be worried about one statement generating more code than another is a false economy. You should be much more concerned about making sure that your program executes correctly and clearly conveys it's logic to the reader.

[gabzz29]

thanks for the insights, well appriciated

[seeplus]

and why do you want getch() and have #include <conio.h> conio.h isn't standard and isn't portable.

[Ganado]

I think people learning programming for the first time seem to like having a simple function that gives immediate feedback when you press a button, as opposed to needing to press a particular key like "Enter" with a more complicated (albeit standard) call.

But not using goto is definitely a good lesson to learn early.

______________

With regard to the original post: I cannot reproduce your issue. It lets me choose again each time, after I press a key to execute passed the getch().
The caveat here is that if you accidentally entered a non-number into lines 14, 21, or 30, then your input stream will be set to a failure state, and will no longer accept input.

[seeplus]

a simple function that gives immediate feedback when you press a button, as opposed to needing to press a particular key like "Enter" with a more complicated (albeit standard) call.

Yep. Why can't this feature be part of the standard? Same as providing a standard for kbhit()