General • Re: C program, flush input, scanf(), menus, etc.

Code:

// Menus - state machine using pointer to function// you can set up a callback function to handle user input asynchronously#include "pico/printf.h"#include "pico/stdio.h"#include "pico/time.h"// #include <stdio.h>volatile bool input_available = false; // Flag to indicate if input is availablevolatile char input_char = 0; // Variable to store the input character// Define function prototypes for state-handler functionsvoid mainMenu();void exitMenu();void state1();void state2();// Define function prototypes for character input callbackchar getInputChar();void inputCallback();// Pointer to the current state-handler functionvoid (*currentState)() = mainMenu;void inputCallback(void *param) {    input_available = true; // Set the flag to indicate input is available    input_char = getchar(); // Read the input character}char getInputChar() {    input_available = false; // Reset the input flag    return input_char; // Return the input character}// Main menu state-handler functionvoid mainMenu() {    printf("\n\nExample Menu:\n");    printf("1. Choice One\n");    printf("2. Choice Two\n");    int choice;    printf("Enter your choice (1 or 2): ");    while (!input_available) {        sleep_ms(10); // Wait for input to be available    }    choice = getInputChar() - '0'; // Convert char to int    // switch calls state function    switch (choice) {        case 1:            currentState = state1;            break;        case 2:            currentState = state2;            break;        default:            printf("Invalid choice");            sleep_ms(1000);            break;    }}// example, state 1 (do work)void state1() {    printf("state 1, do stuff here");    sleep_ms(1000);    currentState = mainMenu;}// example, state 2 (other work)void state2() {    printf("state 2, do other stuff here");    sleep_ms(1000);    currentState = mainMenu;}int main() {    stdio_init_all(); // set up serial    sleep_ms(2000); // give serial time to init?    stdio_set_chars_available_callback(inputCallback, NULL); // Set the input callback    // do the state-handler forever    while (1) {        currentState();    }    return 0;}